From Kurma’s blog… (http://www.kurma.net/faq/q1.html)

The below is my most-often-asked question. Today Miss Harsha Advani from Pune,
India, wrote and asked it again:

“…my query is why shouldn’t onion and garlic be consumed in sattvic (mode of goodness) diet? What are it’s side effects or consequences?”

My reply:

Dear Miss Advani,

You may know that onions and garlic are botanical members of the Allium
family – along with leeks, chives and shallots. According to Ayurveda,
India’s classic medical science, foods are grouped into three categories –
sattvic, rajasic and tamasic – foods in the modes of goodness, passion and
ignorance. Onions and garlic, and the other Alliums are classified as
rajasic and to some extent tamasic, which means that they increase passion
and to some degree ignorance.

Those that subscribe to pure brahmana-style cooking of India, including
myself, and Vaishnavas – followers of Lord Vishnu, Rama and Krishna – like
to only cook with foods from the sattvic category.
These foods include fresh fruits, vegetables and herbs, dairy products,
grains and legumes, and so on. Specifically, Vaisnavas do not like to cook
with rajasic or tamasic foods because they are unfit to offer to the Deity.

Rajasic and tamasic foods are also not used because they are detrimental to
meditation and devotions. Of course some of the Alliums have specific health
benefits; garlic is respected as a natural antibiotic. In recent years, the
cardiovascular implications of vegetable Alliums has been studied in some
detail, although the clinical implications of onion and garlic consumption
from this point of view are not well understood (Block 1992; Briggs et al.
2001).
Nevertheless, despite medical comings and goings, alliums are still avoided
by spiritual adherents because they stimulate the central nervous system,
can act as a natural aphrodisiac, and disturb meditation.

You may be aware that strict Buddhists also do not eat any of the Alliums
for the same reasons as adherents of India’s Ayurveda – they disturb
meditation. If you visit any strict vegetarian Thai, Vietnamese, Chinese, or
Japanese restaurant anywhere in the world you will most likely find no
Alliums in any of the cooking.

One reason is because 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.

That in a nutshell is why I don’t cook with garlic and onions.

Kurma