Aspirin, also known as acetylsalicylic acid. is made of carbon,hydrogen, and oxygen atoms. The formula for aspirin is C9H8O4. It contains compounds found in plants such as the willow tree and myrtle. Bark of the willow tree would be used to stop paining or swelling before aspirin was a thing. Now aspirin is used to relieve pain, reduce fever lowering inflammation, in higher doses. It works on headaches, cold or flu sprains and strains menstrual cramps long-term conditions, such as arthritis and migraine. Some side effects are upset stomach, heartburn, drowsiness, or mild headache. Aspirin has a bitter taste. Its density is 1.40 g mL-1. Its melting point is 135 ºC and in higher temperature it decomposes. It is soluble in water, ethanol, ethyl ether and chloroform.