Garlic and Onion are botanical members of the alliaceous family (alliums) – along with leeks, chives and shallots. As well as producing offensive breath and body odour, these (alliaceous) plants induce aggravation, agitation, anxiety and aggression. Thus they are harmful physically, emotionally, mentally and spiritually.
According to Ayurveda, India’s classic medical science, foods are group into three categories – sattvic, rajasic and tamasic – foods in the modes of goodness, passion and ignorance. Onions and garlic, and the other alliaceous plants are classified as rajasic and tamasic, which means that they increase passion and ignorance. They cause a disturbance, and even pain and sickness to those who eat them. In spiritual life one should cultivate the mode of goodness and avoid the lower modes.
In Bhagavad Gita (17.9) Krsna states that ‘Foods that are too bitter, too sour, salty, hot, pungent, dry and burning are dear to those in the mode of passion. Such foods cause distress, misery and disease.’ Onion and garlic fall in this category. They excite the baser instincts and make it difficult for one to control the senses. The prohibition on onion, garlic etc. is implicit, by virtue of their characteristics.
Homeopathic medicine comes to the same conclusion when it recognizes that red onion produces a dry cough, watery eyes, sneezing, runny nose and other familiar cold-related symptoms when consumed. Back in the 1980’s, in his research on human brain function, Dr Robert [Bob] C. Beck, DSc. found that garlic has a detrimental effect on the brain. He found that in fact garlic is toxic to humans because its sulphone hydroxyl ions penetrate the blood-brain barrier and are poisonous to brain cells.
Also in ancient Buddhist Tao writings, one sage Tsang-Tsze described the Alliums as the “five fragrant or spicy scented vegetables”. And that each have a detrimental effect on one of the following five organs – liver, spleen, lungs, kidneys, and heart. Tsang-Tsze said that these pungent vegetables contain five different kinds of enzymes which cause “reactions of repulsive breath, extra-foul odour from perspiration and bowel movements, and lead to lewd indulgences, enhance agitations, anxieties and aggressiveness,” especially when eaten raw.
Satvic foods provide mental peace, it keeps our mind calm. Helps us speak the truth and always keeps our mind under control. This is the main reason as to why Brahmins preferred eating only Satvic foods. Foods that come under the category of rajas can make you want and desire worldy pleasures. Onions are known to increase your sexual feelings. This is one of the main reasons as to why onions were restricted in the earlier times. The qualities that we get when we eat foods in the Tamas category, such as onions and garlic, is that our mind becomes evil. We tend to be more angry and our mind can never be got under control.
Though some people believe that garlic helps to cure certain health disorders. However, Brahmins found alternative ayurvedic medicines to cure the same diseases. We humans do not have a control over our minds. So, by avoiding foods like onions, garlic, meat, etc, Brahmins believe that it is a step towards attaining peace and fulfilling the purpose of their life.