Manglik Dosh, also known as Mangal Dosh, is an important concept in Indian astrology. It occurs when the planet Mars is positioned in the 1st, 4th, 7th, 8th, or 12th house of a person's birth chart. This dosh is believed to have a negative impact on marriage and married life.

Mars, considered the God of War, is unmarried by nature. When it occupies these specific houses in a person's horoscope, it is said to create obstacles and problems in marriage. It is believed that Manglik individuals must marry another Manglik person to nullify the negative effects of Manglik Dosh. Without this, the individual may experience hardships in their marriage, and in some cases, even the death of their spouse.

In astrology, if a Manglik marries a non-Manglik, it is believed that there will be constant struggles, dissatisfaction, and sometimes even the death of the partner. To remove these malefic effects, Mangliks are often advised to marry a Manglik, or in some cases, marry a Peepal tree, Shaligram, or a water pitcher before their actual wedding to eliminate the 'death yoga' from their horoscope.

However, astrology also suggests that once the person reaches the age of 28 or 29, the Manglik Dosh automatically fades, allowing them to marry anyone.

It's important to note that this information is based on astrology, and while it holds significance for many, it is not scientifically proven.