The banned substance linked to Manny Ramirez is commonly taken by steroid users but also can be prescribed for other conditions.

A person familiar with the details of the suspension said Ramirez used the female fertility drug HCG, or human chorionic gonadotropin. The person spoke to The Associated Press on condition of anonymity because the banned substance wasn't announced.

HCG, added to baseball's banned substances list last year, is popular among users of performance-enhancing drugs because it can mitigate the side effects of ending a cycle of steroids. The body may stop producing testosterone when a user goes off steroids, which can cause sperm counts to decrease and testicles to shrink.

"They use (HCG) to essentially jump start testosterone production," said Ruth Wood, an expert in steroid abuse at the University of Southern California.

The drug could have appropriate uses unconnected to steroid abuse, said Dr. Gary Wadler, who leads the committee that determines the banned-substances list for the World Anti-Doping Agency. HCG can treat male infertility and testosterone deficiency, he said.

"It's not necessarily the drug of choice, but those are acceptable uses," Wadler said.

Ramirez said in a statement he did not take steroids but that a doctor gave him medication for "a personal health issue."

Every baseball player is tested each year within five days of reporting to spring training and again at a randomly selected unannounced date. There are 1,200 additional unannounced tests of randomly selected players, including up to 375 during the offseasons from 2008 through the start of spring training in 2011.

"We have no knowledge of the Ramirez case, but it's highly unlikely an otherwise healthy, young athlete would need HCG for a legitimate medical reason," said U.S. Anti-Doping Agency CEO Travis Tygart. "That said, if there was valid medical need, his high-priced representatives should be fired for not ensuring that he was informed of the process that could have granted him permission to use it."

Athletes in the BALCO scandal have been linked to the female fertility drug Clomid.

Side effects of HCG include headache, mood swings and depression, Wadler said. The anti-doping community has been familiar with HCG for more than 20 years, he added.

HCG is prescribed to treat infertility in women by triggering ovulation. The hormone naturally occurs in pregnant women — home pregnancy kits test for one portion of the HCG molecule, Wood said.