Robinson Cano’s failed drug test — and the subsequent 80-game suspension handed to him — came not directly because of performance-enhancing drugs, but as a result of Cano’s use of Furosemide.

Usually prescribed to treat high blood pressure, Furosemide is a diuretic. To put it more simply, it makes you pee a lot. Its relevance to Major League Baseball is that the drug can be used as a masking agent for PEDs. Furosemide itself isn’t against the league’s rules, but if MLB determines a player was using it as a masking agent, the drug triggers a positive test. This seems to be the case in regards to Cano.

“Furosemide is used to treat various medical conditions in the United States and the Dominican Republic,” Cano said in part in a statement issued by the Major League Players Association. “This substance was given to me by a licensed doctor in the Dominican Republic to treat a medical ailment. While I did not realize at the time that I was given a medication that was banned, I obviously now wish that I had been more careful.”

Furosemide, normally sold under the brand name Lasix, blocks sodium, chloride and water from being reabsorbed into the blood before becoming urine, thus causing an increase in urination. It’s commonly used in race horses to prevent them from bleeding.

Dehydration and dizziness are among its side effects. It can be used as a masking agent by reducing the amount of drugs in the urine, thus making them harder to detect.

Though he admitted to using Furosemide, Cano adamantly denied taking PEDs in the statement.

“I would never do anything to cheat the rules of the game that I love,” he said, “and after undergoing dozens of drug tests for more than a decade, I have never tested positive for a Performance Enhancing Substance for the simple reason that I have never taken one.”