First, agree the plan with your vet
Before technique comes permission: ask your vet exactly how this medication should be given. Some oral medicines must go in by syringe on an empty mouth because food interferes with them; others are perfectly safe stirred into a small feed. Some can be mixed with something sticky and sweet to carry the taste; others lose their effect if crushed or mixed. Ask also what to do about a spat-out portion — whether to repeat it, partly repeat it or wait — because the answer differs by medicine, and guessing can mean doubling. And ask the practice to show you the syringe technique once, in person: two minutes of demonstration is worth a week of wrestling.
The syringe method, step by step
Have the loaded syringe ready before you approach, and work in a stable or enclosed space with a helper holding the lead rope if the horse is a known battler. Stand at the left shoulder, slide your hand along the muzzle, and slip the syringe nozzle into the corner of the mouth, into the toothless gap between the front teeth and the molars — never force it between clenched teeth. Angle it upward and over the tongue toward the back of the mouth, then depress the plunger in one steady motion. Keep the head raised slightly for a few seconds afterwards and stroke the underside of the jaw; most horses swallow in response. Letting the head drop the instant the plunger is home is how medication ends up dribbled down the chin.
When feed is the carrier
If your vet approves food delivery, make the medicated portion small — a handful, not a bucket — so the whole portion is eaten in a few mouthfuls, and stay to watch it go down rather than leaving it in a feed left overnight. Sticky carriers help paste and powders cling to feed instead of sifting to the bottom. Give the medicated handful first, before the main feed, while the horse is hungry and least suspicious. Watch for the horse that learns: if he starts refusing the carrier food or sorting through it, tell your vet rather than escalating the disguise war, because a horse that stops trusting his feed is a bigger problem than the medication round.
Safety and honesty in the process
Keep your fingers out of the mouth itself — the toothless gap is for the syringe nozzle, not your hand — and stand close to the shoulder rather than in front, where a head-toss lands. Work calmly and quickly; a long, escalating struggle teaches the horse that medication time is a fight, and tomorrow gets harder. If a significant part of the medication is spat out, note honestly how much you think was lost and follow the plan you agreed with the vet, rather than topping up by eye. If the horse becomes genuinely dangerous to medicate, say so: there may be a different formulation or route your vet can use instead.
Retraining the reluctant horse
Outside medication times, rebuild the association: practise with a syringe of something the horse likes, in the same position, ending with praise and a scratch, a few times a week. Most 'haters' are horses who learned that the syringe predicts a bitter mouthful and a wrestling match; a run of pleasant rehearsals, plus a treat immediately after the real medication if your vet allows it, softens the reflex surprisingly fast. Pair that with a visible routine — same time, same place, same handler where possible — and the job steadily shrinks.
Logging every administration in KinsLe's Care Teams, with the time it was actually given, means a second handler never guesses whether the horse has had it — the commonest medication accident in shared yards is a medication given twice.