No. We are always learning. For many illnesses we can only provide symptomatic care, meaning we can only treat the signs and symptoms, not the cause. In some cases the treatment is curative, meaning that yes, we can provide the "answers" to cure the condition, and in some cases we can only provide palliative care, meaning comfort while dying. I would say that for the vast majority of ailments we can only provide symptomatic care. Fortunately in some serious conditions such as heart disease, we have surgery which is curative, if only temporary in some cases. In many illnesses, such as insulin dependent diabetes, we have the science to be able to know how to provide what the body is lacking and to prevent further damage from the condition.