New Hampshire Gov. Chris Sununu has vetoed a bill that would have allowed pharmacists to give out ivermectin to treat COVID-19 without a prescription.

Ivermectin is a cheap anti-parasite drug to which some patients have turned for coronavirus treatment. Health experts want to stop people from doing so, warning that ivermectin can cause harmful side effects and that there’s little evidence it helps.

The Granite state only has four instances in which pharmacists can give out medication without a prescription. Those are for smoking cessation, for contraception, for treatment of a substance use disorder and for treatment for sexual assault. Sununu said that in all four circumstances, the drugs involved have undergone rigorous reviews. He also noted that ivermectin has not gone through such reviews as a COVID treatment.