Those close to me know that I've had many longstanding issues with some kind of gastritis and it has recently been worse, so naturally I was researching some options for spiritual intervention. I already knew about the 18th lunar mansion's spirit Egribel (Picatrix Book 4, ch. 9, pg. 290 Warnock/Greer edition), and have an image I made in the past (not entirely happy with, can do better) but her time to come around again is next month, July 17. I really need something much sooner..
Another working in Picatrix is an image of the sign Cancer (Book 2, ch 12, pg 122 Warnock/Greer). Quoth: "It's image is to be placed on the stomach for all its infirmities" and has some really hard to match conditions for just anytime.
This same chapter also mentions an image of Libra for "all infirmities of the stomach" as well with similar difficulty in electing, and I may need to read it more closely but the text as given may have some contradiction in it.
Another possibility is Venus, I have a good talisman of Venus already and can do work in her hour. Picatrix (Book 4, Ch 4, pg 245 W/G) says to "Ask from Venus.. invigorating the appetite". A challenge I have here is my natal Venus is afflicted and weak, so it may take more effort to woo Venus's favor in this regard for me than some other planets I might appeal to for other things.
Also Book 3, Ch. 7 (pg 158 W/G) holds that the Moon may be appealed to for "a great appetite for eating". I have a good Moon talisman as well and that is something I can work with, the Moon is not especially strong for me but is not afflicted either.
Emotions are very important to the organs of digestion, and Jupiter is well known as the planet of Peace. While there are not workings in Picatrix as subtle as those for "peace of mind and body" he would be appropriate to invoke balance in one's condition, Marsilio Ficino has some things to say about Jupiter's role in this in his Three Books On Life, I may dig that out later for an exact reference. Jupiter hour would be very appropriate for balancing activities such as zazen or meditation, yoga or tai chi.
I hope this is helpful to other seekers who are challenged by these matters of the stomach and appetite.
Copies of the compleat Picatrix in English can be obtained from Renaissance Astrology