When Mangal is located in any one of the 1,4,7,8 or 12th house, the chart has "Mangal Dosh"
1st house - Impact on Personality, short tempered
4th house - Impact on career and father
7th house - Impact on wealth, family.
8th house - Impact on siblings, communication skills.
12th house - Impact on spending, health.
The astrological combination is also referred as Kuja and person born in presence of this condition is referred as Manglik.
Although the negative effects are likely, yet they can be resolved or reduced with several remedies like "Kumbh Vivah" or marrying a person with planets cancelling this effect.
Puja can be performed for resolving the Manglik Dosh