1. Good for aching joints but they hurt your guts. (6)

4. This cell may be a bit to the side – but that does not matter, does its job well. Keeps the acid flowing. (8)

7. Cave in Greek but part of the stomach for those who speak English only. (6)

9. Maybe good for anthrax and similar conditions -but why are they used for ulcers? (11)

11. U.S. Army surgeon stitched up 3 down – did not do it well, but got glory anyway. (8)

12. Strong stuff, makes you itch, burn, flare and wheeze. (9)

14. Found in 4 across – keeps the action going. Stopping it, good for heart burn. (6,4)

17. His name may sound a bit dark, but he is a shining white knight for those who had heart aches and heart burns. Was well rewarded (see 10 down) (5)

18. Common term – can cause disease or just annoy. Spies may plant one. (3)

19. Vital nerve - 10^th of 12; keeps the heart and stomach working. (5)

20. Five membered ring contains nitrogen – central part of 12 across. (9)

2. Common over-the-counter drug - belongs to the same class as 1 across. (3)

3. Tough French Canadian – brought glory to 11 across, outlived him too. (2,6)

4. Another cell close to 4 across, adds another component to flowing juices. (6)

5. Maybe against, but added to 12 across soothes itch. (4)

6. Like 12 across, stimulant for 4 across. (7)

8. Acronym for important ubiquitous enzyme – can be affected by 1 across. (3)

10. Reward for work well done. Given to 17 across and 14 down. Not to 11 across, 16 down since they died too soon. (5,5)

11. First name of down-under scientist – swallowed bugs to prove his point – may get 10 down. (5)

12. Spiral critter – causes much damage. (1,6)

13. Short for powerful "Stuff" released from 19 across. (3)

14. He did a lot more than ring bell for slobbering dogs. Got his just rewards though. (6)

15. Had a hole in his stomach. Was studied by a Dr. Wolf. (3)

16. Found what made stomach juices acid. Foresaw a version of the Periodic Table. (5)