The drugs used for chemotherapy have the unfortunate side effect of stripping the protective coating from nerve endings, resulting in tingling, numbness, pain, and loss of balance. The damage can last up to 15 weeks or even be permanent. The amino acid L-glutamine has been shown to speed up the repair process, but your parent needs to take a lot of it to get noticeable benefits. So skip the 500-milligram capsules and buy the powdered form popular with bodybuilders instead. Take two scoops twice a day (studies used 15 grams twice a day) mixed with a liquid such as juice or Gatorade.

Sources

http://www.hrpca.org/glutamine.htm