If you or a friend is having a coughing fit...

1 Give them Poppy seeds to start with, and make them more tired.

2 Wait and see if that works. If it doesn't, then give them Juniper Berries. It may not be as good for the body, but it is stronger and it should work. The Juniper berries will also cure their belly aches, because it is most likely that after all the coughing, their stomach would hurt.

3 They should be asleep by now because of the poppy seeds that you gave them earlier. Now, just let them  rest, and hopefully, after they wake up, all your hard work will have paid off.