Answer: There are several common reasons for regurgitation in captive snakes. Physical stress while the snake is digesting can be caused by handling the snake, disturbing or moving the cage or if you have loud noises that may cause the cage to vibrate. One case I know about the snake was on the shelf next to a speaker. When the music was loud the snake was disturbed and it regurgitated.
Another reason for regurgitation is a snake’s inability to thermoregulate. Your pet must be able to maintain optimal temperature for digestion. As a responsible keeper, you need to provide a temperature gradient. A temperature gradient means one side of your cage is warmer than the other. To create a temperature gradient use a heat lamp at one end of the cage. This end of the cage should be used for basking. Use a thermometer to make sure the basking area is at the optimal temperature. The other end of the cage should be cooler and darker. This allows the snake to choose the right temperature, something your snake is much better at than any snake keeper.
Make sure the mouse is the proper size for your snake. If the mouse is frozen, make sure the mouse is completely thawed. The mouse should not be fed in an environment where the snake could ingest substrates.
Since your snake has regurgitated you should not offer another mouse for a week. Offer only clean fresh water. Next time you feed offer a mouse that is smaller than you normally feed and only offer one mouse at a time. This routine should be followed for several feedings.
Following this stress relief regimen should solve your problem. It is time to seek help from a vet if you see any other signs of sickness or if your snake continues to regurgitate.