Type B adverse drug reactions (ADRs) are often serious, limit the usefulness of drugs that are otherwise effective, and increase the risks of drug development as they often lead to postmarketing withdrawal. There is evidence that susceptibility to at least some Type B ADRs is under strong genetic influence. Identifying genes in which variation influences susceptibility has obvious practical value for genetic testing and might also make it easier to screen molecules likely to cause ADRs at an early stage of the drug development process. Research in this area is hampered by the lack of a resource in which to study genetic determinants of susceptibility to Type B ADRs. As serious Type B ADRs are rare, case–control designs are the most frequently-used approach. The EUDRAGENE collaboration seeks to develop a resource using an international collaboration. This will provide a basis for adverse drug susceptibility genome association-wide studies using tag single nucleotide polymorphisms, or a direct approach using putative functional polymorphisms.