Grok Takes #1 in Medicine But Has the Worst Hallucination Rate

Anthropic made Opus dumber (73% Drop), Claude Code Hits $2.… · Apr 18, 2026 Health & Fitness

Grok topped the medicine text arena benchmark, but Vectara's separate test showed it has a 20.2% hallucination rate — the highest of any frontier model. Healthcare is the last place you want an AI that confidently makes things up.