Rahu is a shadow planet in vedic astrology. Rahu has the capacity to turn life of natives like few other planets and combinations can do in a horoscope. A good Rahu in horoscope could turn a beggar into a king and a bad Rahu could turn a king into a beggar. Certain symptoms and associations in horoscope are signs of a weak Rahu

1. Reckless investments and debts due to it are sure to have influence of Rahu.
2. Reckless marriage based on impulsive desires and divorce afterwards is also most likely due to Rahu.
3. Negative fame and humiliations in public life could also be due to bad Rahu. For example many celebrities who get criticised for moment of reckless behavior are likely to be under Rahu's influence at that time.
4. Rahu often gives success to an undeserving person and than make his unworthiness to be seen in public.
5. Creating unnecessary debts, addiction to sex, alcohol and drugs and many other similar bad habits are under influence of Rahu.
6. In a horoscope association of Rahu with Jupiter creates Vipra-Chandal Yoga. Rahu along with Saturn causes Shaapit Yoga which is due to past life sins. Though Shaapit Yoga occurs only after 30 years people born during those period are troubled a lot.
7. Rahu's association with Sun and Moon in horoscope causes Grahan Yoga which makes the native lose objectivity and rational thinking. This is turn causes mental diseases, debts and other troubles in natives life.

     The Ishta Devta for Rahu is Goddess Durga. But one could also pray to Lord Shiva, Varaha Form of Lord Vishna and Kaal Bhairav form of Lord Shiva can also be prayed by natives with weak Rahu. Rahu is a poser. Any God who teaches simplicity and well-being of others like Kaal-Bhairav and Varaha are ideal. The great sage Ved Vyas composed the Rahu Japa Mantra which could lessen the effects of weak Rahu.

Rahu Japa Mantra

अर्धकायं महावीर्यं चंद्रादित्य विमर्दनम् |
सिंहिकागर्भसंभूतं तं राहुं प्रणमाम्यहम् ||

Ardha-kaayam Mahaa-veeryam Chandra-aditya Vimardanam
Simhika-garbha Sambootam tam Rahum Pranamamyaham

Rahu Gayatri Mantra

om naakadhwajaaya vidmahae padma hastaaya dheemahi tanno raahu: prachodayaat

     Rahu is one of the agents which cause mental diseases. So regular Pranayam especially Anulom Vilom and Bhastrika Pranayam is essential. Anulom Vilom regulates dopamine and serotonin levels in brain which keeps a check on mental diseases. Also fast jogging is helpful to remove depression and other mental ailments.

     Rahu causes illusions and also mental diseases. Ideal food for natives with weak Rahu is boiled Mung Bean(Vigna radiata) at night. Also important are foods which improves the mood like banana. Food rich in starch and fiber like whole wheat bread/roti, corn, carrots, potatoes, cereal flakes with bran and others should be consumed a lot by natives with weak Rahu to avoid mental diseases and to stay healthy and fit.

     Natives with weak Rahu should donate green clothes and green vegetables, pulses and other green or yellowish food to the poor. If the native is wealthy than donation of green emerald to relatives would also help lessen effects.

     But the biggest favor natives with weak Rahu could do is to be simple, honest and respectful to others around. All the problems associated with Rahu are due to natives having been over-smart and having conned others previously. Karma catches up and turns them into total fools. Better to heed the advise and start living an honest existence. Otherwise worse would follow.