Biological substances are defined by the Biological Substances Ordinance as:

• Microorganisms (in particular bacteria, viruses, fungi and protozoa),
• cell cultures of animal and plant origin,
• human pathogenic endoparasites,
• genetically modified microorganisms, cell cultures, endoparasites,
• Agents associated with transmissible spongioform encephalopathy (prion proteins, e.g. as causative agents of BSE/mad cow disease),
• ectoparasites,
• engineered biological entities,

which can cause infectious diseases and illnesses in humans due to their possible sensitising or toxic effects or have other harmful effects.

Further specialised information can be found under Safe working in the laboratory of the German Social Accident Insurance Institution for the raw materials and chemical industry (BG RCI).