I`ve seen elsewhere that when got food poisoning, that we need to take two tablets, but having checked everything in the UI, I can`t get anything like "Use" to appear or "Actions" to become unghosted.

http://thelongdark.wikia.com/wiki/Antibiotics

I had a bottle of 16 & even tried dropping 14 to the floor to use the remaining 2, to no avail.

Anyone else had this &/or found a fix or how to get them to work?
I`m at 51%hp now, eeeeeeeeeeek!

Press the Tab key to enter the status display. Under the Ailments the food poisoning is listed and there is a button for using first aid to get better. After that you also need to rest for ten hours.

I had tried that first, knew the routine after having fixed a sprained wrist, but it didn`t work for the food poisoning.

It should work this way. It worked this way since the whole game because public Alpha (although with many different UI versions).
If you can't open your stats with TAB and go to the heal condition page where you can apply medication or you just can't apply the medication... you might have discovered a bug. Please report it on with a detailed description and screenshots on the Hinterland Forums. :)
http://hinterlandforums.com/

I`ll try it again next time I play, but I died on that character so that, sort of, solved my problem ;)

Shall keep peepers open for it again though.