In this issue of JAMA, a study by Harlow and colleagues found that 11% of US high school seniors (ie, 12th grade) reported using Δ 8 -tetrahdyrocannabinol (Δ 8 -THC) in the past 12 months based on a 2023 survey. 1 This study is a reminder that there is a diverse set of cannabis products on the market that vary in their legal and regulatory status and potential for harm. 2-5 Δ 8 -THC is a psychoactive cannabinoid that can be derived from hemp. 2,3 It was introduced to the retail market in 2018 and there are indications that its use is on the rise. 4 There is little regulatory oversight of production and sales of Δ 8 -THC and some evidence of adverse outcomes after use. 2,3,5 The unregulated proliferation of Δ 8 -THC represents a potential threat to the public's health. 2,3 In this editorial, we review the legislation that led to the widespread availability of Δ 8 -THC and describe its behavioral pharmacology and potential health harms. This information will assist health professionals in advocating for stronger regulatory oversight of cannabis products and may be useful to health care professionals with patients who use or are considering using Δ 8 -THC.