What is Rahu Mahadasha Rahu Antardasha? What are the effects of rahu mahadasha? & how to survive it? Get accurate Rahu Mahadasha remedies from below. Rahu Mahadosh is the period of 18 years when Rahu lays impact on the native’s life. This impact can be positive or negative depending upon the horoscope of the native. According to the Vedic astrology, Rahu is one of the malefic planets that causes various adverse effects. Some Rahu Mahadasha effects are sudden loss of wealth, chronic diseases, marital issues, family conflicts, decline in mental abilities etc.