The 39-year-old, who first found television fame as a spotty student in the sit-com The Young Ones, suffered head injuries when his quad bike turned over during a drive around his farm near East Allington in Devon.
His wife Barbara said that she was optimistic. "We will have to wait and see, but we are very hopeful," she said. The couple, who have been married for 12 years, have three children: Rosie, 11, Sidney, 9, and Bonnie, 2.
Mrs Mayall is believed to have found her husband unconscious under the four-wheeled bike on Thursday night when she came out of their home to see why the engine had stopped.
A spokesman at Derriford Hospital, Plymouth, said Mr Mayall was now stable and that his condition was not expected to change in the next few days.
Because of his serious injuries, Mr Mayall was flown to hospital by police helicopter.
Rik Mayall is one of the original Comic Strip team of comedians and starred in the comedy series Bottom and in the ITV political satire The New Statesman.
Channel 4 is due to show a special Comic Strip retrospective tonight called The Comic Strip Presents ... Four Men in a Car and were last night waiting for news of the health of its star.
A spokeswoman said: "We are very shocked to hear of Rik's accident and will be monitoring his situation closely before making a decision whether or not to go ahead with the transmission."