The biological systems are opened and are kept far from thermodynamics equilibrium. For these reasons, biological systems are always exposed to external perturbations, which may produce alterations on these rhythms as a consequence of coupling synchronization of the autonomous oscillator with perturbation. Coupling of therapeutic perturbations, such as drugs and radiation, on biological systems delivery to biological rhythms is known as chronotherapy. We used the Rössler system as a theoretical model for chronotherapy, generalized this formalism for chaotic behaviour. We found that when the Rössler is more dissipative, such as c increase, the systems become more robust to the perturbations.