Do you occasionally suffer from a headache, fever, or sore muscles? Aspirin, tylenol, and ibuprofen are all going to be safe choices. Others, however, really need to steer clear of certain over-the-counter painkillers, and then there's the fact that some painkillers work better for different purposes.
Which over-the-counter painkiller should you choose?
What is it?
Aspirin, or acetylsalicylic acid, has been around since 1838, and this OTC medication, which belongs to the non-steroidal anti-inflammatory drug class, is still popular. Approximately 43 million US adults — 19 percent of the population — take aspirin at least three times a week, for more than three months of the year. 
Commonly used as a fever reducer and pain reliever, aspirin has an added benefit that other analgesics don't; it's also an antiplatelet drug, a type of blood thinner, that helps prevent thrombosis. People at risk of heart attack and stroke are often told to use it in low doses (75-100 mg) for this reason. Its reputation as a protector of heart health may be the very thing that's caused it to rise in popularity again over recent years , but watch out — the very same mechanism by which aspirin helps prevent blood clots puts some users at risk of serious bleeding.
Who shouldn't use aspirin?
You should have a chat with your doctor or pharmacist before taking aspirin or any of the numerous products containing aspirin if:
- You are over 60.
- You have had stomach ulcers or bleeding events in the past.
- You're already using another blood thinner, use steroids, or frequently use other NSAIDs.
- You're quite a heavy drinker — three or more alcoholic beverages daily. 
Anyone should consult their doctor if they're using any over-the-counter pain reliever on a daily or near-daily basis, and in addition, it's clear that you shouldn't take aspirin without your doctor's say-so if you suffer from any kind of bleeding disorder, have uncontrolled hypertension, or suffer from asthma. Due to the possibility of Reye's Syndrome, aspirin should not be given to children under 16 either. 
Who can safely use aspirin?
Most people, including you if you don't fall into any of the categories described above, but not on a daily basis. Aspirin isn't the most effective drug for most kinds of pain, but it generally does a great job at sending headaches packing. While you should always consult your doctor prior to taking aspirin during pregnancy, low-dose aspirin hasn't been shown to be dangerous for pregnant women. Some women with blood clotting disorders (thrombophilia) who have suffered recurrent miscarriages may actually be advised to take baby aspirin to prevent miscarriage. 
What is it?
Tylenol, paracetamol, or acetaminophen — whatever you call this fever reducer and analgesic, 23 percent of the US population uses it during any given week. It's not an anti-inflammatory, but tylenol is one of the safest over-the-counter painkillers out there, especially for children and other people who shouldn't be using NSAIDs. 
Who shouldn't use paracetamol?
Tylenol, too, comes with potential risks and side effects. This OTC med shouldn't be used by anyone with liver problems (including those who drink too much), plus, if you keep popping tylenol like it's candy, you'll probably end up with liver problems even if you didn't have any to start out with. As always, consult your physician before you start relying on any over-the-counter drug on a very regular basis. Also give your doctor a call if you experience swelling, redness, hives, itching, and difficulty breathing, as these symptoms indicate that you are having an allergic reaction to tylenol. 
Who should take tylenol?
Tylenol is great for people seeking quick pain relief for mild to moderate pain and headaches, and it will effectively reduce fevers. Acetaminophen is a great option for people who aren't allowed to take NSAIDs because of other medications they are on, for children, and for people who have (had) stomach issues. Again, though, it isn't meant to be taken for longer periods of time — get in touch with your doctor if you feel you need it for longer than a few days.
What is it?
Ibuprofen is a very popular NSAID. The fact that ibuprofen provides relief to sore muscles, osteoarthritis and rheumatoid arthritis pains besides reducing fevers and acting as a general painkiller makes it very appealing to a subset of the population. FDA-approved as a prescription drug in 1974 and made available over the counter a decade later, more than 20 million prescriptions are filed for ibuprofen and medications containing it today — and that doesn't even include over the counter use! 
Who shouldn't take ibuprofen?
While ibuprofen offers distinct benefits, it also carries risks that simply don't come with tylenol or aspirin. Its use rarely causes acute liver failure , and can lead to ulcers, bleeding, and holes in your intestines and stomach. Even more alarmingly, it can also induce a heart attack or stroke in some people. The risk of these adverse events is higher among people who make regular use of ibuprofen, especially if they also smoke, have a family history of heart disease, or suffer from diabetes or hypertension. No person who has recently suffered a heart attack or stroke should use ibuprofen. People taking ACE inhibitors should also steer clear of this drug. 
Seek emergency medical attention right away if you (or someone else, who can no longer act on their own behalf) suffer from the following symptoms after taking ibuprofen:
- Chest pain
- Dyspnea (shortness of breath)
- Weakness or paralysis on side of the body
- Difficulty engaging in speech 
Who should take ibuprofen?
People with arthritic pains or other short-term inflammatory conditions, including sore muscles after excessive exercise, will especially benefit from ibuprofen, though it also certainly takes care of headaches, fevers, and mild pain. Ibuprofen may also be given to children. Nobody should, however, take it for extended periods of time without consulting their doctor and weighing the pros and cons, considering the very real risk of adverse reactions.