In every day medical practice, adverse immune reactions induced by antituberculous agents occur less frequently compared to toxic reactions. The risk of their appearance is significantly greater during individualized regimens. They include severe and potentially fatal reactions such as: anaphylaxis, toxic epidermal necrolysis, severe immune cytopenia, which must be rapidly recognized and monitored in intensive care. Reintroducing the therapeutic agent after suppressing the reaction can prove the causal relationship with an inductor. This diagnostic test (challenge test) is contraindicated for severe adverse drug reactions. The suspicion of an immune reaction during the treatment with antituberculous agents should be followed by the withdrawal of the suspected drug and pharmacological management according to the type and severity of the reaction; lately the antituberculous regimen will be reassessed.