Red eyes feel like there is a foreign body inside, which may be related to conjunctivitis, eye stones, foreign bodies and so on. 1. Conjunctivitis: it is mostly caused by microbial infection and external stimulation, resulting in inflammation of the conjunctiva, showing symptoms such as edema and congestion, so it will feel like there is a foreign body sensation. 2. Ocular stones: mostly by the accumulation of epithelial cells and mucus concentration in the conjunctiva of the condensate, the stone protrudes from the conjunctival surface, will cause eye discomfort, red eyes, foreign body sensation. 3. foreign body: when a foreign body enters the eye, such as gravel, animal hair, eyelashes, etc., it will stimulate the eye to cause congestion and redness, as well as lead to foreign body sensation in the eye. When the eyes are red and feel like there is a foreign body inside, it is recommended to consult a doctor in a timely manner, follow the doctor’s instructions for further relevant examinations, with the help of the doctor to clarify the cause, and targeted treatment or therapy.