diff --git a/code/modules/reagents/chemistry/reagents/other_reagents.dm b/code/modules/reagents/chemistry/reagents/other_reagents.dm
index 804ab97cc7a5..a2c72cfd2183 100644
--- a/code/modules/reagents/chemistry/reagents/other_reagents.dm
+++ b/code/modules/reagents/chemistry/reagents/other_reagents.dm
@@ -102,12 +102,13 @@
 	taste_description = "slime"
 
 /datum/reagent/vaccine/reaction_mob(mob/living/L, method=TOUCH, reac_volume)
-	if(islist(data) && (method == INGEST || method == INJECT))
-		for(var/thing in L.diseases)
-			var/datum/disease/D = thing
-			if(D.GetDiseaseID() in data)
-				D.cure()
-		L.disease_resistances |= data
+	if(reac_volume > 5) //needs at least a certain amount for it to take effect
+		if(islist(data) && (method == INGEST || method == INJECT))
+			for(var/thing in L.diseases)
+				var/datum/disease/D = thing
+				if(D.GetDiseaseID() in data)
+					D.cure()
+			L.disease_resistances |= data
 
 /datum/reagent/vaccine/on_merge(list/data)
 	if(istype(data))