Below is an extract from Longman Dictionary of Comtemporary English: !! Do not say 'suggest (someone) to do something'. You can use the following structures: suggest that somebody do something • He suggested that we go (NOT suggested us to go) for a drink. You can miss out 'that' • What do you suggest we do (NOT suggest us to do)? suggest doing something • I suggest wearing (NOT suggest to wear) something warm. suggest something • She suggested a walk before dinner. I don't understand why it is ungrammatical to say "suggest to do something". I would regard the infinitive "to do something" as a object (noun phrase), similar to the "wearing "(gerund used as a noun) or "a walk"(noun). Can you guys "suggest" any reasons behind?