Manglik Dosh

This condition is astrologically believed to be unfavourable for marriages, causing discomfort and tension in relationship, leading to severe disharmony among the spouses and eventually to other bigger problems. This is attributed to the "fiery" nature of Mars, the planet of war. 
Also, if two mangliks marry, the negative effects are believed to cancel each other out. However, Mars is not the only planet in Vedic Astrology that is supposed to affect the relationship and these effects should be seen in a broader perspective of overall astrological compatibility. 
There is also a belief that the negative consequences for a single-manglik marriage can be resolved if the manglik first performs a ceremony called a kumbh vivah, in which the manglik "marries" a banana tree, a peepal tree, or a silver or gold idol of the Hindu God Vishnu. 
The bad effects of Manglik Dosh can be reduced with the help of astrological remedies which would generally include the application of Pooja, Mantras, Gemstones and Charities and these remedies are different for different individuals depending upon their horoscopes.