I have studied medical science for the greater part of my life, and the person who taught me most was my guru. Therefore, I pay my respects to the science and the teachers. Although many people criticize medical science, I don't endorse their views. Like every other science, modern medicine has its own role to play in human health. Of course it has its limitations, but we should accept them just as we do in the practices of yoga. Yes, yoga has its limitations too. For example, if a person is suffering from typhoid, you don't ask him to practise bhastrika pranayama. You know what can happen if he does.
Throughout the ages, the thinking men have evolved different systems for the treatment of disease. One of the best and most scientific systems is ayurveda, a science which grew up amongst the Hindu people. Then there is another wonderful science called homeopathy. It is a very natural science which has greatly reduced the cost of treating illnesses and disease. In India we are very grateful to homeopathy because whereas modern medicine can cost hundreds of thousands of rupees, homoeopathic remedies may not even cost you one rupee. Of course, the most widespread system of treatment is the modern science of allopathy. So, we should have respect for all the sciences.
However, we should not believe that medicine can give us health. Health is always a positive aspect and not a negative one. When you take a pill to ensure sound sleep, the kind of sleep that results is of a negative quality. If you want to overcome insomnia in a positive way, you must change your environment, go to the mountains for a short holiday, have some exercise, run a little bit, then you will be able to sleep well. This is positive health. Instead of taking medicine when you don't feel like eating, just fast for one day; that will give you positive health. But if you take a little medicine and eat after that, it is negative health.
Negative health is totally unreliable; it can break down at any moment. Positive health is very reliable and you do not have to depend on any external agencies. You may or may not know it, but your body can manufacture its own antibiotics, cortisone, adrenalin and so on. We have only to discover the means of tapping our internal source.
The simplest way to do this is to fast for one day per week, or once in a fortnight. If you find it too difficult to fast, then take a salt less diet, or abstain from all animal products, which includes milk, curd, cheese and butter, for a considerable period of time. By doing this, the toxins will be eliminated, and at the same time, the cause of the disease. Once the body is free of toxins, the natural antibodies will begin to flow through the body.
Therefore, with all respect to the medical sciences, I think they should only be used in emergency cases. For instance, you can't practise yoga on the battlefield. If a soldier is suffering from catarrh, you have to make him better quickly so you can put him back into action. As a matter of fact, the medical sciences were mainly developed during wartime, because it was vitally important to ensure rapid relief to the soldiers so they could be back in the battle lines the next morning. If the soldiers remained in their tents practising yoga nidra for two weeks the whole country would surely be lost. So, we should not speak against the doctors and surgeons.
My guru, Swami Sivananda, was a doctor holding the degree of FRCS. Once I asked him, 'Why did you abandon the medical profession?' He answered, 'Man's maladies are beyond the scope of medicine. Medicines cannot cure his sufferings and they cannot take away his sorrows. Medicines cannot help him in overcoming his passions, and that is why I have accepted yoga in place of medicine.' And this is exactly my own situation.