These is no Siddhi Prayoga recommended for this Mantra, which means that it can be used without Mastering it by chanting a prescribed number of Mantra Chants.
A little amount of the Vibhuti or the Ash, which has fallen off from the Agarbatti or Dhoop, which has been lit it the Puja Ghar in the home or in a temple has to be held in the Right Hand and infused by chanting this Mantra, Which, I have given in this post just once with full concentration. The Mantra is known in the Hindi language as the Bacho Ke Pet Ke Rog Ka ilaj Karne Wala Mantra.
Then the Mantra infused Vibhuti should be lightly applied on the stomach of the ailing child. The Mantra Healing Experiment can be carried on daily until the child experiences relief.
ॐ नमो सरस्वती | सब निकली चोली चळी || आगनमो परा || चैली || मेरी भक्ती गुरु कि शक्ती || चलो मंत्र ईश्वर वाचा ||
Om Namo Saraswati | Sab Nikali Choli Chali || Aaganamo Para || Chaili || Meri Bhakti Guru Ki Shakti || Chalo Mantra Ishvar Vacha ||