If I was not informed of the risks of an operation or treatment, can I claim?

Question

José Manuel Alburquerque · Accepted Answer

Yes. Before an operation or treatment, the doctor must explain to you what it is for, what it involves, what risks it carries and what alternatives there are. To receive compensation, the general requirements are that a risk you were not informed of materialised, that it caused you harm and that, had you been properly informed, you could have decided differently. According to a March 2026 judgment of the “Tribunal Supremo”, Spain's Supreme Court, what is paid in that case is not a fixed sum but a percentage of the total harm, set according to the likelihood that you would have chosen another option. If there was also an error in the way you were operated on or treated, all the harm caused by that error is compensated. What you must be told The information must be truthful and understandable and must enable you to choose between the available options. Before asking for your signature, the doctor must also explain the contraindications, the likely risks and those that depend on your personal circumstances, such as your age or other illnesses. In practice, these are the points most often disputed: For an operation, an invasive test or treatment and, in general, where there are significant risks, consent must be given in writing. In other cases verbal consent is enough, although what you were told must be recorded in your medical records. You must be told about the typical risks of that procedure, including rare ones if they are serious. There is no need to explain unforeseeable or exceptional risks. If you say you were not informed, it is normally up to the doctor or the medical centre to prove that you were. Informing you can only be dispensed with in exceptional cases, such as a serious emergency in which it is not possible to ask for your permission. How compensation is calculated If the doctor acted correctly from a technical point of view, the physical harm is not due to an error in the operation or treatment. What is compensated in that case is the chance you lost to decide differently, which the courts call loss of chance. The Supreme Court applied this in its judgment 374/2026 of 10 March to a woman who had already had a caesarean section and whose labour was managed as a vaginal birth without her being properly told about its risks or about the alternative of scheduling another caesarean. The risk of uterine rupture was between 0,32 % and 0,47 %, compared with around 0,03 % with a caesarean. Her uterus ruptured and her daughter suffered a serious brain injury. The court of first instance and the “Audiencia Provincial”, the provincial appeal court, had awarded a fixed sum of 10.000 euros for non-pecuniary damage (distress). The Supreme Court replaced it with 20 % of the total harm, this being the probability it estimated that the mother, properly informed, would have chosen the caesarean. That came to 200.000 euros for the daughter and 1.077,96 euros for the mother, plus interest. To set the percentage, account is taken of the seriousness of the risk that was not explained, the alternatives available, whether the procedure was necessary or elective and how likely it is that you would have refused it. In elective medicine, such as cosmetic treatment, this loss usually carries more weight, because the patient could have chosen not to have the operation. If almost any patient would have accepted the procedure anyway, the percentage will be low. Where there is no significant physical harm, some courts have recognised non-pecuniary damage for the lack of information alone, especially in elective or cosmetic medicine, although this cannot be taken for granted. How to claim Ask for a copy of your medical records, including the consent forms. In Catalonia they are kept for at least fifteen years. Commission a medical expert to assess whether the information was sufficient and whether any error was also made. If you were treated by the public health service, submit a claim to the public authorities for compensation based on their “responsabilidad patrimonial”, their liability in damages, within one year of your recovery or of when the after-effects stabilise. If you were treated privately, make a written claim against the doctor, the clinic and their insurers as soon as possible, preferably within the first year. Before suing them, you must try to reach an agreement, for example through a written proposal to negotiate, as the law has required since 2025.