Patients are advised to use Merlin every 4-6 hours, and the number of applications should not exceed four in 24 hours. If the fever symptoms are not effectively relieved after three days of continuous use, the patient should promptly go to the hospital for medical consultation to find the cause of the fever and regular treatment for the cause. The main component of Merlin is ibuprofen, a non-steroidal anti-inflammatory drug. After taking the drug, it will have certain side effects on the body, the more common is to cause gastrointestinal discomfort, such as stomach pain, acid reflux, nausea, vomiting, loss of appetite, and in severe cases, even peptic ulcers and bleeding. Ibuprofen can also cause damage to liver and kidney function when taken in excess. If the interval is too short or the number of doses is too many, the above-mentioned adverse reactions will easily occur. Usually, it is clinically recommended to apply short-term moderate amount and not to overdose or overtime. If the effect is not good after taking, it may be that the patient is not sensitive to this type of drug and can be replaced by another drug, such as acetaminophen, but the interval between each other should also be 4-6 hours.