Yes. Eligible travelers can receive medical treatment in the UK with a UK ETA within the permitted visitor conditions.
However, a UK ETA is not a long-term stay visa, so medical visits should generally be within 6 months. If your treatment will last longer than 6 months or requires a long-term stay, you should check whether a separate visa is required instead of a UK ETA.
During immigration checks, you may be asked to show treatment appointment details, proof that you can pay for the treatment, accommodation information, and your return or onward travel plan.
If you plan to receive medical treatment in the UK, please check your treatment period and required documents before applying for a UK ETA.