Dietary supplements are enormously popular. With an economic impact of $159 billion (2023), it is somewhat (but not much) smaller than Big Pharma at $800 billion (2022). The category includes thousands of products, generally consumed with the aim of health improvement or maintenance. Some supplements have defined ingredients that have been well studied, where the risk of toxicity is understood. Other supplements may be sourced from plants (e.g., herbs) and by definition will be multi-ingredient – after all, herbal remedies with medicinal effects are effectively unrefined drugs. Toxicity risks with herbal remedies may be less clear, owing to their different and varying constituents. Because there is generally less regulation of supplements versus prescription or over-the-counter drugs, there may also be discrepancies between what’s on the label compared to what’s actually in the bottle, increasing the uncertainty about what you’re actually buying when you buy a herbal remedy.