Substance abuse, rape among fellow prisoners, needle exchanges, deplorable hygiene, psychiatry, old age in prison: the prisoner is a " person at risk due to his environment". Nevertheless, prisoners, who are users of a public service, must not be deprived of the capacity to claim their fundamental human rights. The protection of health is a human right, linked to a duty of the state which must ensure it. No one can harm the health of others, not even a penitentiary etablishment.In this context, the Public Health and Social Protection law of January 18 th, 1994 was a real turnaround in custodial spheres. It gave responsibility for prisoner’s health to the public hospital service. Yet, although this law was a great step forward in the effective recognition of prisoners’ rights, the reconciliation of the imperative of security with the respect of such rights still poses problems today. The issues today go beyond the simple medical aspect. They achieve the basic principles of criminal law and procedure both at national and European level.Indeed, under the impetus of international and European developments, our law has acquired a status for prisoners, including that of the right to health protection, which has become a fundamental right. However, if this development has enabled considerable progress in the effectiveness of the right to care for detainees, difficulties remain and have been revealed even today by the health crisis linked to Covid-19, since the right to protection of health must be reconciled with the imperative of security.While health-related issues are now included in the case law of the Court of Cassation and the European Court, the harmonization of this law with criminal law must however go through an affirmation of the protection of the rights of the detainee. This protection must be twofold: substantive and procedural.Being a subjective right, the right to protection of the prisoner’s health should take into account the differences with that of the free population. It demands positive discrimination in terms of procedural guarantees, in particular the right to an effective remedy. Despite the loss of autonomy that detention entails and its security imperatives, the detainee who finds himself in a suitable legal situation must be able to seize the procedural opportunities.For issues such as the responsibility and the behavior of fault-committing health care providers, risk exposure factors related to prison and law enforcement, or to the responsibility of the prison authorities, are among these legal situations If prison health care workers are to work in close conjunction with the prison administration, the courts must also be involved so that the medical condition of the detainee can be taken into account in all their decisions and sentences can be individualized. However, the particular context of prison time and confinement makes it difficult to implement these substantive and procedural principles: the health crisis linked to Covid is a recent perfect example.