Bethenny Frankel is dealing with a major health issue … she says she was just diagnosed with stage 2 chronic kidney disease.

The ‘RHONY’ star announced the health update Thursday on social media, encouraging folks to go see their doctor to get their blood work done.

Bethenny says she was referred to a specialist after blood tests raised red flags with her kidney function … and that’s when she found out about her condition.

It’s interesting … Bethenny says she’s been told her chronic disease could be autoimmune or it could have been caused by a traumatic experience she had years ago, where she almost died from an allergic attack. She says the allergy issue may have damaged her kidneys.

Moving forward, Bethenny says she’s got to do a better job drinking water and staying hydrated, and she’s got to cut out ice cream, which may be hard … she was enjoying some frozen dessert as she filmed her post.