This is a good question & it varies with how well you know the people you work with and the type of company you work for. If it’s a smaller business and you have strong personal relationships with your manager or your boss, then it may be a good idea to let them know what’s going on with your health. You can start a dialogue such as “I’ve been having some health issues with my digestive system as of late. I am trying to find ways to manage it, but it might be a long term thing.” If there are things about your job duties that may need to be changed, it might be best to be open about it.
For example if you normally have to travel long distances, perhaps you can stop traveling for a short period and help out closer to the home-base or perhaps this will help people understand why you’re needing to leave a meeting halfway through to use the restroom.
The alternative is to not tell your employer & it is unfortunate for me to tell you that this might be a wise move depending on your employer, especially if you’re in the United States where your health insurance is tied to your employer.
If you are in a company where you do not have strong personal relationships, you’re in a larger company where you are more like a number than a person or you’re in a higher pressure job, exhibiting any sort of weakness or reason you might not be able to do your job might put you on the shortlist for people who might not be working for the company very long. Legally discrimination due to health is not allowed, but in most companies you can be let go for any reason and they don’t have to tell you why.
A darker more paranoid scenario may even see someone within the company purposefully using your condition against you, perhaps in a bid to make themselves look better or to save the company money. In most cases if you voluntarily quit you are not eligible for unemployment benefits.
The only way you’re protected from this is if you fall into the guidelines of the Family & Medical Leave Act(U.S. Law), unfortunately this requires your doctor to fill out paperwork and many doctors have a phobia about filling out this paperwork. Many just prescribe some drugs, imply you’re trying to dupe them into some sort of fraud because you’re lazy & then send you on your way.
If you are interested in filling out FMLA paperwork, talk to your doctor first and make sure they are on-board. Then speak with your Human Resources department as they usually will have special forms to fill out.