Headache — what do you take? Menstrual cramps? Toothache? Standing in the pharmacy aisle, the choices look endless. But here's the thing: dozens of products, only a handful of actual ingredients. Learn the ingredients and choosing gets easy — and more importantly, you avoid the dangerous mistake of doubling up.
1. How do you choose. The shelf looks endless but pain relievers split into two families — NSAIDs for pain with swelling or inflammation (cramps, toothache, muscle pain), acetaminophen for plain headache or fever. This split is our own way of choosing — what the agencies actually say is in the FDA and NHS lines below.
2. The most dangerous mistake. Doubling up. Cold and flu combinations already contain acetaminophen, so adding a headache tablet stacks it without you noticing — the FDA says the ingredient is in more than 600 medicines and sets 4,000 mg a day as the maximum — an overdose damages the liver.
3. The reliable route. This is general information, not a diagnosis or prescription. The same symptom has different causes, and your conditions or medications can create risky combinations — asking a pharmacist is free, fast and the most reliable way to choose.
Know these two and you are halfway there
Over-the-counter pain relievers split into two families. They behave very differently.
| Acetaminophen | NSAIDs | |
|---|---|---|
| Common names | Tylenol (paracetamol) | Ibuprofen (Advil, Motrin), Naproxen (Aleve) |
| Reduces inflammation? | No | Yes — swelling, inflamed pain |
| Best for | Ordinary headache, fever, mild aches | Cramps, toothache, muscle/joint pain, sprains |
| Stomach | Gentler (OK on an empty stomach) | Can irritate → take with food |
| Main organ risk | Liver (overdose can be serious) | Stomach and kidneys |
The one-line rule. Inflammatory pain (cramps, toothache, muscle pain) → NSAIDs. Plain headache or fever → acetaminophen. This is our own rule of thumb, and so is the “Stomach” row of the table. The NHS ibuprofen page says to take it with or after food.
What do you take for what
Headache
For an ordinary headache, try acetaminophen first. If it doesn't help, an NSAID is a reasonable next step.
- Some headache products contain caffeine (it boosts the effect — but can keep you up at night)
- The NHS headaches page lists “taking too many painkillers” as a common cause, and says to see a GP if you regularly get headaches or they are not getting better or are getting worse
Menstrual cramps
The NHS period pain page says to use painkillers like paracetamol (acetaminophen) or ibuprofen. It does not say which works better, so neither do we.
- Take ibuprofen with or after food (NHS)
- Periods that become more painful, heavier or irregular, period pain that stops your usual activities, or bleeding between periods — see a doctor (NHS period pain)
Toothache
The NHS paracetamol and ibuprofen pages say adults can take the two together if needed, but suggest trying each on its own first. They do not say the combination works better. For the toothache itself, see toothache (NHS).
Important. Painkillers mask the pain; they don't fix the cause. The decay or infection keeps progressing. See a dentist. Medication is only for getting through until then.
Cold and flu
Cold medicines are often multi-ingredient combination products — which is exactly where people get into trouble.
- Fever/aches — acetaminophen (in most combination cold products)
- Runny nose/sneezing — antihistamines (can cause drowsiness → don't drive)
- Congestion — decongestants like pseudoephedrine (can raise heart rate; caution with high blood pressure)
- Cough — cough suppressants / mucus — expectorants
Pick only what matches your symptoms. If you just have a runny nose, you don't need a product that also contains a cough suppressant.
The most dangerous mistake
Cold medicine + Tylenol = too much acetaminophen. Most combination cold products already contain acetaminophen. Adding Tylenol on top means taking a double dose of the same drug. Acetaminophen overdose can cause serious liver damage.
Always read the active ingredients on the package. Different brand names can contain the same drug.
- Acetaminophen — the FDA maximum is 4,000mg a day; the Korean label for Tylenol 500mg also says 4g (8 tablets) a day; the NHS says no more than 8 x 500mg tablets in 24 hours, 4 hours apart. Products differ, so follow the label
- Alcohol — the FDA says to talk to a health care professional if you drink three or more drinks a day; the NHS says you can drink normally. The agencies word it differently
- Don't take two different NSAIDs at once — the NHS says not to take ibuprofen with other NSAIDs such as naproxen or aspirin
How much is too much — 600 and 4,000
Why doubling up is dangerous comes down to two numbers. Transcribed from the US Food and Drug Administration, checked 30 July 2026.
| Item | FDA source text |
|---|---|
| How many medicines contain it | “over 600 prescription and nonprescription medicines” contain acetaminophen |
| Daily maximum | “no more than 4,000 milligrams a day” |
| If you exceed it | “can cause serious liver damage” · “too much acetaminophen can lead to liver failure and death” |
| Alcohol | “talk to a health care professional if you drink three or more alcoholic drinks a day” |
| Where to look | the ingredients section of the Drug Facts label |
| Children | “never guess the dose.” If the label has no dose for your child's weight or age, ask a health care professional |
“Over 600” is the number that matters here. Counting the pain reliever bottle is not enough — cold and flu remedies and some prescription medicines carry the same ingredient.
How many tablets a day actually fit
| Situation | From cold medicine | Headroom left | Max 500mg tablets |
|---|---|---|---|
| Pain reliever alone | 0mg | 4,000mg | 8 |
| Cold medicine 325mg × 3 a day | 975mg | 3,025mg | 6 |
| Cold medicine 500mg × 3 a day | 1,500mg | 2,500mg | 5 |
Same pain reliever, but the ceiling moves from 8 tablets to 5 depending on what else you take (our calculation). Remember “8 is fine” and you will exceed the maximum on the day you catch a cold.
The assumption, stated plainly. Acetaminophen content in cold remedies varies by product. The 325mg and 500mg above are illustrative, and you have to read the Drug Facts on the product you actually take. On 22 September 2026 we checked two Korean products against the Ministry of Food and Drug Safety’s licensing records: Tylenol Cold-S tablets contain 325 mg per tablet, three times a day (975 mg a day, the table’s second row), and Pancol-A oral solution 300 mg per 30 mL bottle, three times a day (900 mg). The 500 mg row stays an example; we did not survey the whole market.
And the Korean label goes further than this table. The licensing record for Tylenol 500 mg tablets says not to exceed “4 grams (8 tablets) a day” and warns that it “must not be taken together with other products containing acetaminophen.” The table shows how much margin disappears when doses overlap by accident; it is not permission to combine them. On a cold-remedy day, do not add a separate pain reliever — ask a pharmacist.
Pain relievers split into two families
The FDA separates acetaminophen from NSAIDs. The NSAID ingredients named on the page are ibuprofen and naproxen.
| Item | Acetaminophen | NSAIDs (ibuprofen, naproxen) |
|---|---|---|
| What the FDA says it does | “temporarily relieves pain and temporarily reduces fever” | treated as a separate drug class |
| Main warning | liver damage and liver failure | — |
| Added 2024 | a rare serious skin reaction warning | referenced as the comparison in that context |
The page does not spell out the gastrointestinal bleeding or cardiovascular warnings for NSAIDs, so we did not transcribe them. They are widely known, but writing only what we verified is this blog's standard (see below).
When to ask first
These are the cases the NHS ibuprofen page says to check before taking it. With acetaminophen or cold remedies, ask a pharmacist first too if you have a long-term condition.
- Pregnancy — avoid ibuprofen unless a doctor or pharmacist advises it
- A stomach ulcer now or in the past
- A heart, liver or kidney condition
- Taking blood pressure medicines or anticoagulants such as warfarin
- Giving medicine to a child — the FDA says “never guess the dose”
When to stop self-treating
Times not to tough it out with tablets, in the agencies’ own words.
- A headache you have treated yourself that is not getting better or is getting worse, or you regularly get headaches — GP (NHS headaches)
- A headache that started suddenly and is extremely painful, with a very high temperature or stiff neck, light bothering you, numbness or weakness in the body or face, trouble speaking or walking, or drowsiness or confusion — 999 or A&E (NHS headaches)
- You have taken more acetaminophen than the packet says — get help now (NHS 111; if told to go to A&E, do not drive)
- Possible serious side effects from ibuprofen, such as a swollen throat or tongue — get help now (NHS ibuprofen)
Painkillers quiet the symptom — they don't fix the cause. If they are not helping, or you keep needing them, use the thresholds above.
Correction (15 October 2026). The opening summary said the FDA sets “600 mg per dose”. That was wrong — the 600 on the FDA page is the number of medicines (more than 600) containing the ingredient, not a dose. Also fixed: “3,000–4,000mg” is now the FDA, Korean label and NHS values; “never mix with alcohol” is now the FDA and NHS wording; for period pain, “NSAIDs work better, prostaglandins, take early” and for toothache “more effective together” are replaced with NHS wording, unsourced parts removed; “several days”-style thresholds are now the NHS headache and medicine pages. The two-family rule is marked as our own.
For hives the NHS says to ask a pharmacist about antihistamines (hives); for chickenpox it says not to use ibuprofen unless a doctor tells you to (chickenpox).
Sources
- NHS — agency source — Paracetamol for adults (reviewed 24 March 2026), Ibuprofen for adults (reviewed 27 August 2025), Period pain (reviewed 18 March 2026), Headaches (checked 15 October 2026). Source for 8 x 500mg tablets in 24 hours 4 hours apart, adults taking both together (each alone first), no other NSAIDs alongside ibuprofen, taking it with food, who should check first, period pain painkillers and when to see a doctor, “taking too many painkillers” as a headache cause with the GP and 999 thresholds, and 111 after an overdose.
- US Food and Drug Administration — agency source — “Don’t Overuse Acetaminophen” (checked 30 July 2026). Source for over 600 medicines containing it, the 4,000mg daily maximum, liver damage, the three-drinks-a-day advice, checking the Drug Facts ingredients section, and never guessing a child's dose.
- US Food and Drug Administration — agency source — “Acetaminophen” (checked 30 July 2026). Source for the split between acetaminophen and NSAIDs, the NSAID ingredients named (ibuprofen and naproxen), “liver failure and death,” and the rare serious skin reaction warning added in 2024.
- Our own calculation. 8 tablets alone, 6 alongside 325mg cold medicine, 5 alongside 500mg is 4,000mg less the cold-medicine share, divided by 500mg — not a table the FDA publishes.
Where to check further
- Korean standards and per-product content. At first Korea’s drug safety pages would not open and only FDA data was used; on 22 September 2026 we checked three Korean products (Tylenol 500 mg, Tylenol Cold-S, Pancol-A) in the licensing database and added them above. For anything else — Korea's drug information service lets you look up ingredients by product name, and the box itself is the most reliable source.
- NSAID gastrointestinal and cardiovascular warnings, and duration limits. Widely known, but not stated on the FDA page we opened, so not carried over — a pharmacist answers this against your own conditions.
- Whether 4,000 mg is your ceiling too. It can change with body weight, liver function and other medication, and the page gives no conditional values — with liver disease or regular drinking, get your own limit from a doctor.
As of July 2026. The figures and wording come from US FDA pages; the tablet arithmetic is ours. Choosing medicines at a US pharmacy is in our drugstore guide part 1 and part 2, travel supplies in the first aid kit article and the packing guide, and urgent care in the ER versus clinic article.
This article is general health information and does not replace medical diagnosis or prescription. Talk to a pharmacist or doctor when choosing a medicine or dose, and always read the label for directions and warnings.
