Here are premium pet‑food brands and specific lines that are commonly recommended for pets with sensitive stomachs (dogs and cats), plus quick notes on when to use prescription vs. over‑the‑counter options and practical tips.

Top veterinary (prescription) options — best for chronic or severe GI problems or for a formal elimination/hydrolyzed diet trial

• Royal Canin Veterinary Diet — Gastrointestinal / Digestive Care (dog & cat veterinary lines for easy digestion, prebiotics, fiber balance). (royalcanin.com)
• Hill’s Prescription Diet — i/d (digestive care) and z/d (hydrolyzed / food‑sensitivity formula). These are formulated by veterinary nutritionists for GI recovery and allergy elimination trials. (petsmart.com)
• Purina Pro Plan Veterinary Diets — EN (Gastroenteric) and related GI therapeutic formulas (highly digestible, energy‑dense options for GI disease). (petsmart.com)

Why these matter: veterinary prescription diets are recommended when signs are severe, persistent, or when a controlled elimination/hydrolyzed diet trial is needed — prescription (hydrolyzed or veterinary novel‑protein) diets are used because manufacturing controls and formulation reduce cross‑contamination and improve diagnostic reliability. (mspca.org)

Premium over‑the‑counter formulas often used for milder sensitivities

• Hill’s Science Diet — Sensitive Stomach & Skin (dog & cat non‑prescription line using highly digestible ingredients and prebiotic fiber). (hillspet.com)
• Purina Pro Plan — Sensitive Skin & Stomach (contains prebiotics and guaranteed live probiotics in some formulas; oatmeal/oat meal options). (purina.com)
• Blue Buffalo — True Solutions / Digestive Care (prebiotic fiber, formulated for digestive support). (bluebuffalo.com)

Limited‑ingredient, novel‑protein, and boutique premium brands (good options if your pet tolerates non‑prescription diets)

• Natural Balance L.I.D. (Limited Ingredient Diets) — single‑source proteins intended to avoid common triggers. (naturalbalanceinc.com)
• Zignature (Select Cuts / Limited Ingredient formulas) — novel proteins (fish, venison, rabbit) and limited recipes that many owners use for food sensitivities. (zignature.com)
• Other premium LID lines to consider: Canidae Pure, Nutro Limited Ingredient, Blue Buffalo Basics, Wellness Simple — look for “limited ingredients,” single protein source, or novel proteins (venison, duck, rabbit, fish).

Practical tips

• See a veterinarian first if your pet has weight loss, frequent vomiting, bloody stools, severe diarrhea, or other concerning signs — those need veterinary evaluation and possibly a prescription therapeutic diet. (avmajournals.avma.org)
• For suspected food allergy or chronic skin + GI signs, vets usually recommend an elimination trial (8–12 weeks) using a novel‑protein or hydrolyzed prescription diet; hydrolyzed diets can be especially useful in diagnosis because the proteins are broken down to reduce allergenicity. Don’t do a home “mix” for a formal trial — use a single, controlled diet and avoid treats/table scraps. (mspca.org)
• Transition slowly: mix new food with the old over ~7–10 days (or longer for very sensitive pets); stop or slow the transition if vomiting/diarrhea appears and contact your vet if problems persist. (petmd.com)
• Wet food can be gentler and more hydrating (especially for cats). Many sensitive‑stomach lines are available in both wet and dry formats. (businessinsider.com)
• Read labels carefully: “limited ingredient,” “novel protein,” “hydrolyzed protein,” “prebiotic/probiotic” and “highly digestible” are key terms to watch for. Over‑the‑counter LID/novel‑protein diets vary in manufacturing controls — for formal elimination trials, vets often recommend veterinary prescription options for reliability. (veterinarypracticenews.com)

If you want a short, tailored shortlist:

• For a mild/more common sensitivity (you just want a premium OTC): Hill’s Science Diet Sensitive Stomach & Skin; Purina Pro Plan Sensitive Skin & Stomach; Blue Buffalo Digestive Care. (hillspet.com)
• For suspected food allergy or persistent problems: ask your vet about Hill’s Prescription Diet z/d or i/d, Royal Canin Gastrointestinal, or Purina Pro Plan Veterinary Diets EN. (petsmart.com)
• For owners preferring limited‑ingredient boutique options (non‑prescription): Natural Balance L.I.D., Zignature, Canidae Pure — but be aware of variable manufacturing/control differences compared with vet diets. (naturalbalanceinc.com)

If you tell me whether this is for a dog or a cat, the pet’s age/weight, and the main symptoms (diarrhea, vomiting, chronic soft stools, chronic itchy skin, etc.), I can give a tighter shortlist of specific formulas and links to product pages.