Two classic oral medications that are widely used around the world, recommended by the World Health Organization (WHO), are suitable for both young and old, affordable and safe to use: acetaminophen and ibuprofen. Acetaminophen is the first choice for children and adults over 3 months of age. The name of this medicine is a bit tongue-in-cheek and may not be familiar to you, but you should not be unfamiliar with the names of drugs like paracetamol, Piriton or Tylenol, which are different names for the same medicine, all containing a single active ingredient “acetaminophen”. They are different names for the same drug, both containing a single active ingredient, acetaminophen, to reduce fever. The maximum daily dose of acetaminophen for children is 15 mg per kilogram of body weight, every 4 hours, up to 4 times a day. For example, if your baby weighs 10 kg, the maximum dose you can give is 150 mg per dose, and if the acetaminophen concentration you have is 100 mg per ml of drops, then the 150 mg dose translates into a feeding volume of 1.5 ml. Any dosage below this is safe, but should not be exceeded. Acetaminophen can be used by both pregnant and nursing women without harming the fetus or affecting the nursing baby. Acetaminophen is safe at reasonable doses, but taking more than the maximum dose can cause liver damage. Commonly used compound cold medicines often contain the ingredient “acetaminophen”, such as children’s aminoglutethimide granules, aminoglutethimide granules, aminoglutethimide syrup, phenomethimide suspension, and adults with day and night pepto-bismol, white plus black cold tablets, etc.. If you take single-ingredient acetaminophen to reduce fever while also taking the above-mentioned compound cold medicines, it is easy to overdose on acetaminophen due to repeated medication, so check the ingredients carefully before taking the medicine and avoid stacking medicines containing the same active ingredients. In addition to the liquid form of acetaminophen, there is another form of acetaminophen: the form of anal administration, i.e. suppositories. In foreign countries, anal dosing is actually quite common, but due to our culture, the majority of Chinese people have difficulty accepting this form of medication. However, in some cases, such as when giving medicine to a baby who vomits, or when a baby has a high fever at night and you don’t want to wake the baby up, it is much easier to use an anal suppository. The absorption of suppositories does not go through the liver and does not irritate the gastrointestinal tract, and it works faster than the oral way because the drug goes directly from the intestinal mucosa into the bloodstream. However, from the point of view of absorption rate, oral absorption rate is high, while suppositories absorb the drug through the mucous membrane, and the absorption rate is a little lower. Ibuprofen is indicated for the reduction of fever in children over 6 months of age and adults with sericosis, a genetic glucose-6-phosphate dehydrogenase (G6PD) deficiency, acetaminophen should be avoided, but ibuprofen can be used. Ibuprofen may also be considered to reduce fever in patients who have failed to reduce fever with acetaminophen. Well-known medications that use ibuprofen as a single active ingredient include Merlin and Fenpropathrin. The maximum daily dosage of ibuprofen for children is 10 mg per kg of body weight per dose, every 6 hours, up to 4 times a day. The regular dosage for adults is 200 to 400 mg per dose, every 6 to 8 hours, up to 4 times a day, with a maximum dose of 2400 mg a day. It is safe to use any dose that does not exceed the maximum. Ibuprofen has a strong antipyretic effect and the process of reducing fever causes the body to sweat a lot, so ibuprofen is not suitable for patients with symptoms of dehydration to reduce fever. Also, ibuprofen is excreted through the kidneys and should be used with caution in patients with poor kidney function. Adverse effects of ibuprofen also include the possibility of inducing asthma and should be used with caution in babies with asthma. This drug is safe when used in the recommended dose, but overdose can easily cause kidney damage. For persistent high fever, consider alternating acetaminophen and ibuprofen. The minimum time interval between acetaminophen doses is 4 hours. When the fever does not go down two hours after the maximum dose of acetaminophen has been used, only ibuprofen can be used alternately, because the minimum time interval between the two drugs is two hours. When alternating, the maximum number of times each drug can be used per day remains the same. It is important to note that when a fever can be reduced with only two or three antipyretics a day, I recommend choosing a single antipyretic because each additional drug doubles the risk of taking the wrong drug. Therefore do not alternate between two kinds of fever-reducing medications when the fever can be controlled with one kind of fever-reducing medication. In addition, drink more water when taking medicine to reduce fever to speed up the excretion process that helps take away body heat. At the same time, it is necessary to take medicine to lower the fever along with physical cooling, such as taking a warm bath or wiping the whole body with a warm wet towel, but do not use alcohol wipes, especially for children, as alcohol can easily pass through the child’s tender skin and lead to alcohol poisoning.