The U.S. Food and Drug Administration has cleared two treatments for irritable bowel syndrome with diarrhea, approving drugs that are both linked to recent merger activity in the sector.

Salix Pharmaceuticals Ltd.’s top-selling antibiotic Xifaxan, already approved for traveler’s diarrhea, now has approval as an IBS treatment. Valeant Pharmaceuticals International Inc. bought Salix for $11.1 billion in April.

Earlier this year, Sterne Agee estimated the expanded use could add $1 billion in yearly sales.

“We are thrilled to offer patients this new option to manage their IBS-D symptoms,” Salix said in a statement.

Xifaxan can be taken orally three times a day for 14 days, according to the FDA.