On mobile this prevents negative effects such as bleeding and you can feed it to your tames and they will have the immunity effect. This is very helpful if you want to fight a wild giga since the bleed effect from the giga’s bite can kill anything within 100 seconds. Doesn’t even matter if you have a trillion hp. However if you feed your mount a lesser antidote you can kill a wild giga with a Rex ez. Still beware tho since a giga without bleed is still about as powerful as a high lvl alpha Rex, so make sure you use a high hp and melee Rex with a good saddle.
I managed to kill a lvl 40 wild giga yesterday with my 30k hp 1.9K melee Rex equipped with a 289 armour saddle and only took 1K dmg with the help of a lesser antidote.