Some admit they plan to take it themselves, but others tell Krzykowski it's for their animals. Either way, he tells customers that he strongly discourages them from taking the medicine.

"You can tell the difference between someone who has cattle and someone who doesn't," Krzykowski said, "And we're seeing a lot of people right now who don't have cattle."

Animal feed stores around North Texas have similar stories about ivermectin, the anti-parasitic drug commonly used for deworming livestock. Some people have turned to the drug in an effort to prevent or recover from COVID-19, with cases spiking throughout the region.

Ivermectin has also gained popularity in Latin America, where it can be purchased in pharmacies for just a few dollars. Some conservative media pundits in the U.S. began touting the drug's effectiveness, with word spreading to social media.

More than a dozen stores in the Dallas/Fort Worth area said they have sold out of the animal medication, with some not knowing when they will receive new shipments. Others said they receive multiple calls each day from people looking for the drug, which comes in paste and injectable forms.

At Walden Farm and Ranch Supply in Weatherford, just west of Fort Worth, ivermectin has been in short supply the last month.