But Atabrine, like quinine, had side effects, including gastritis, hallucinations and psychosis, Masterson wrote. Plus, it turned the skin of GIs and Marines yellow.“The most hair-raising [side effects] were rashes that … progressed grotesquely, with skin falling off in sheets, creating open sores that attracted flies,” Masterson wrote. Other side effects included “erratic mood swings, violent anger, and deep depression …[along with] the standard diarrhea, vomiting, and cramps.”Then came the rumor the drug caused impotence.During the fight for the Pacific island of Guadalcanal, Marines rejected Atabrine. Their officers had to watch them take the pills and make sure the pills were swallowed. But the Marines would later spit them out.Thousands got sick. “For every battle casualty, ten men lay sick with malaria,” Masterson wrote.