The twelfth house is the expenditure house, Mercury is the karaka planet for business or trading. Mercury in the 12th house can cause harm to the native in business. The native may remain troubled by financial problems due to debt etc. Mercury in the twelfth house can make the native indulge in wrong activities. The native may be inclined towards illicit relations. The native will have corrupt thoughts in his mind. The native may have to face humiliation due to his actions. The twelfth house is the causative house of spirituality or salvation. Mercury in the 12th house can make the native inclined towards spirituality. The native can spend his money on religious activities. Mercury in the twelfth house is not considered auspicious for the mother of the native. The native may have to face problems from his mother. The number of children of the native may be less. The native may be inclined towards new subjects. The native may be inclined towards foreign languages.