Agree the log before you need it
Sensitive stomach is a description, not a diagnosis, so home monitoring is how the picture sharpens. Discuss with your vet exactly what to record each day: the food brand, flavour and amount, every treat and scrap, appetite at each meal, vomiting episodes and what they contained, and stool consistency, easiest on a simple scale you both use. Add weekly weight, because slow loss is easy to miss in a longhaired cat you see daily. A fortnight of honest notes often reveals a pattern — one flavour, one treat, one stressful event — that no single consultation could.
One change at a time, judged fairly
Plan the rules of any food trial together. Changing diet, treats and feeding schedule in the same week makes the result unreadable, so agree to alter one variable, hold it steady for the period your vet sets, and judge on the log rather than on one bad day. Ask how gradual the switch to a new food should be, since abrupt changes upset even sturdy stomachs and can fake a failure. Also list the quiet saboteurs to remove during the trial: milk, rich scraps, a second household member's treats, and hunting spoils if your cat goes outdoors.
The red lines you set in advance
Agree the thresholds that end home monitoring and trigger a call: blood in vomit or stool, vomiting repeatedly within a day, complete refusal of food, obvious weight loss, lethargy, or signs of dehydration such as dry gums and loss of skin elasticity. Kittens, senior cats and cats with other conditions get a lower threshold because they dehydrate and decline faster. Ask whether the vet wants a stool sample saved if episodes recur, and how fresh it needs to be, so you are not improvising at midnight.
Feeding routines that protect the evidence
How food is offered can blur the log if it is not standardised. Feed measured amounts at set times during a monitoring period rather than leaving an unmeasured bowl topped up all day, because intake is one of the variables you are trying to read. Keep water in the same place and note refills. If several people feed the cat, agree that whoever feeds, records — an unlogged second breakfast can look exactly like a diet failure. Photographing the stool examples your vet provides, kept beside the log, keeps everyone's scoring consistent across the household. Consistency in the routine is what makes the numbers at the review worth discussing, and it makes any genuine change stand out sooner. If a house-sitter or family member feeds during the trial, leave the log and the rules where the food is kept, not in a drawer.
Review the evidence, then adjust
Bring the log to the review rather than a summary from memory, and go through it with the vet: which days were bad, what preceded them, and whether the trend is improving. The next step might be a different diet trial, tests the log now justifies, or reassurance that the pattern is mild and manageable. Keeping the food history, symptom timeline and weight record in KinsLe's Pet Passport means the monitoring survives between appointments and any vet can read the story at a glance.