Hangover drug. Pills of RU-21, a supplement designed to assist the metabolism of alcohol by the body and reduce the effects of hangover. RU- 21 contains natural ingredients, including dextrose, succinic acid and ascorbic acid (Vitamin C). These work to reduce the accumulation of acetaldehyde, a harmful by-product of alcohol metabolism, and speed its conversion into harmless acetic acid, which is broken down by the body into water and carbon dioxide. Acetaldehyde has been implicated in causing alcohol-related diseases, such as cancers and liver cirrhosis, and may be the agent of alcohol addiction.