© 2019 The Author(s) 2019. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: email@example.com. Recently some authors have suggested that oral valaciclovir 1 g q8h is a valid alternative to intravenous aciclovir for herpes encephalitis. We are concerned about numerous caveats that we think have not been sufficiently addressed to allow such use outside of a controlled research setting.