In this chapter we first set out the epidemiology of Clinical Toxicology, with the most frequent poisonings, and the need for making a register at the national level in order to obtain a more exact understanding of the true scale of the problem is emphasised. We next refer to clinical care and we divide patients depending on whether they have symptoms of: reduction in level of consciousness, alterations in their behaviour (agitation, delirium), generalized convulsions, or if they are conscious patients with different clinical manifestations: cardiac, pulmonary, digestive, nephro-urologic. Reference is also made to the neurotoxicological syndromes that can appear with different poisonings, besides the explorations and analyses that must be carried out to obtain an exact diagnosis of the poisoning. Finally, we deal with the treatment of the patient suffering form poisoning; we emphasise digestive decontamination, antidotes, kidney cleansing and the different poisonings that can be effective for extra-renal cleansing.