the only valid remedy of the pitr dosha is the shraddha ceremony at the gaya and the important tirthas like rameshweram etc. the pitra dosha is supposed to be caused by the "poorva karma dosha " of earlier lives. the pitr dosha causes childlessness, obstacles and faliours.

lord surya supposed to be the remover of this dosha. if sun homam is performed at the samkranti days it helps a lot in pecifying this dosha. proper worship of Pitras on pitra paksha removes this dosha.

best remedy is to observe and celebrate the bhagvata saptah parayana it is supposed to be remover of all pitra doshas to root. worship of lord Narayana and doing vaishnava mantra jaapa for pitras is boon to the saptah parayana of Bhagavata.