There is a point in many neurological ward rounds, arriving at the patient with the complicated undiagnosed neurological disorder, when the question arises—often with uncertainty and a hint of desperation—“Should we try steroids?” Fortunately, help is at hand for a fair number of these patients, as the immunological basis of their illness is being better understood. New autoantibodies are dramatically helping in the diagnosis, and the best approach to treatment is becoming clearer. But what should you do if the antibodies are all negative and the patient has all the features of limbic encephalitis? This question is explored by Sherrini Ahmed and colleagues on page 332 and they come up with some helpful suggestions. …