The article introduces a public, computer-readable resource called SIDER (Side Effects Resource), which connects 888 drugs to 1450 side effect terms. SIDER contains information on the frequency of side effects in patients for one-third of the drug-side effect pairs and for 199 drugs, it also includes the frequency of placebo administration. The resource is designed to facilitate research on drug side effects and their phenotypic effects, which are crucial for understanding mechanisms of action and developing personalized medicines. The authors compiled package inserts from public sources, particularly the US Food and Drug Administration (FDA), using text mining to extract side effect information. They found that most side effects occur for more than one drug class, indicating common molecular mechanisms or off-target effects. SIDER provides a comprehensive database for academic research, with a website (http://sideeffects.embl.de) where users can download the database and explore individual drugs and their side effects. The resource is available under a Creative Commons license and will be periodically updated with new drug labels.The article introduces a public, computer-readable resource called SIDER (Side Effects Resource), which connects 888 drugs to 1450 side effect terms. SIDER contains information on the frequency of side effects in patients for one-third of the drug-side effect pairs and for 199 drugs, it also includes the frequency of placebo administration. The resource is designed to facilitate research on drug side effects and their phenotypic effects, which are crucial for understanding mechanisms of action and developing personalized medicines. The authors compiled package inserts from public sources, particularly the US Food and Drug Administration (FDA), using text mining to extract side effect information. They found that most side effects occur for more than one drug class, indicating common molecular mechanisms or off-target effects. SIDER provides a comprehensive database for academic research, with a website (http://sideeffects.embl.de) where users can download the database and explore individual drugs and their side effects. The resource is available under a Creative Commons license and will be periodically updated with new drug labels.