The onset of action of Tylenol is fast, usually about half an hour after taking the effect is likely to appear. Tylenol, also known as acetaminophen extended-release tablets, is a drug with antipyretic and analgesic functions. Acetaminophen extended-release tablets are composed of two parts: an immediate-release layer and a slow-release layer. The sustained-release layer requires the slow release of acetaminophen, and this part of the sustained-release layer allows the effects of acetaminophen to be maintained for a longer period of time, generally lasting up to 8 hours. Therefore, Tylenol or acetaminophen should be taken every 8 hours, no more than 3 times in 24 hours, as recommended by the instructions or medical advice. When taking Tylenol, it should be noted that people who are allergic to aspirin should use it with caution, and other drugs containing antipyretic and analgesic drugs, such as certain compounded anti-cold drugs, should not be taken at the same time, and people with liver and kidney insufficiency should also use it with caution. At the same time, pay attention to not drinking alcohol or alcoholic beverages while taking this product, keep this product out of the reach of children, and if you need to take it, children must be used under adult supervision.