Use of 'OR' and 'AND' inside IF statement? pl-sql

Can anyone tell me if I can use 'AND/OR' inside if statement inside pl-sql procedure? If I can what is the best method to use?

part My code is like this: `if maxcount>0 or zerocount>0 then dbms_output.put_line('all set');

else dbms_output.put_line('need further steps'); end if;

but the result i am getting from this is not very consistent.