Aspirin to other NSAIDs but also suppresses the normal functioning of platelets. One common adverse effect is an upset stomach. More significant side effects include stomach ulcers, stomach bleeding, and worsening asthma. Bleeding risk is greater among those who are older, drink alcohol, take other NSAIDs, or are on other blood thinners. Aspirin is not recommended in the last part of pregnancy. It is not generally recommended in children with infections because of the risk of Reye syndrome. High doses may result in ringing in the ears. A precursor to aspirin found in leaves from the willow tree has been used
Bark bread known from the 1890s, and in Finland "pettuleipä" (literally "pinewood-bark bread") was produced as ersatz bread during the Finnish Civil War of 1918. Finger sized twigs and branches were collected from deciduous trees and shrubs, and the bark split and the inner bark (the phloem and sometimes the vascular cambium) collected while still fresh. The yellow or green inner bark (depending on tree species) was dried over open fire, in an oven or dried in the sun for a few days. A mortar or mill was used to grind the bark to a fine powder to add to the flour.