diff --git a/mods/ENTITIES/mcl_mobs/combat.lua b/mods/ENTITIES/mcl_mobs/combat.lua
index 99878be2e..d9df817e4 100644
--- a/mods/ENTITIES/mcl_mobs/combat.lua
+++ b/mods/ENTITIES/mcl_mobs/combat.lua
@@ -21,8 +21,6 @@ local function atan(x)
 	end
 end
 
-mcl_mobs.effect_functions = {}
-
 
 -- check if daytime and also if mob is docile during daylight hours
 function mob_class:day_docile()
@@ -1153,9 +1151,8 @@ function mob_class:do_states_attack (dtime)
 							damage_groups = {fleshy = self.damage}
 						}, nil)
 						if self.dealt_effect then
-							mcl_mobs.effect_functions[self.dealt_effect.name](
-								self.attack, self.dealt_effect.factor, self.dealt_effect.dur
-							)
+							mcl_potions.give_effect_by_level(self.dealt_effect.name, self.attack,
+								self.dealt_effect.level, self.dealt_effect.dur)
 						end
 					end
 				else
diff --git a/mods/ENTITIES/mobs_mc/skeleton_wither.lua b/mods/ENTITIES/mobs_mc/skeleton_wither.lua
index c39104f4b..b01fb4b96 100644
--- a/mods/ENTITIES/mobs_mc/skeleton_wither.lua
+++ b/mods/ENTITIES/mobs_mc/skeleton_wither.lua
@@ -98,7 +98,7 @@ mcl_mobs.register_mob("mobs_mc:witherskeleton", {
 	fire_resistant = true,
 	dealt_effect = {
 		name = "withering",
-		factor = 1,
+		level = 1,
 		dur = 10,
 	},
 })
diff --git a/mods/ENTITIES/mobs_mc/spider.lua b/mods/ENTITIES/mobs_mc/spider.lua
index 16f802c09..d01c7afbe 100644
--- a/mods/ENTITIES/mobs_mc/spider.lua
+++ b/mods/ENTITIES/mobs_mc/spider.lua
@@ -138,7 +138,7 @@ cave_spider.sounds = table.copy(spider.sounds)
 cave_spider.sounds.base_pitch = 1.25
 cave_spider.dealt_effect = {
 	name = "poison",
-	factor = 2.5,
+	level = 2,
 	dur = 7,
 }
 mcl_mobs.register_mob("mobs_mc:cave_spider", cave_spider)
diff --git a/mods/ENTITIES/mobs_mc/wither.lua b/mods/ENTITIES/mobs_mc/wither.lua
index f1e1e6e78..252873629 100644
--- a/mods/ENTITIES/mobs_mc/wither.lua
+++ b/mods/ENTITIES/mobs_mc/wither.lua
@@ -349,7 +349,7 @@ mcl_mobs.register_mob("mobs_mc:wither", {
 					mcl_util.deal_damage(objs[n], 8, {type = "magic"})
 					hit_some = true
 				end
-				mcl_mobs.effect_functions["withering"](objs[n], 0.5, 10)
+				mcl_potions.give_effect("withering", objs[n], 2, 10)
 			end
 			if hit_some then
 				mcl_mobs.effect(pos, 32, "mcl_particles_soul_fire_flame.png", 5, 10, self.reach, 1, 0)
@@ -469,7 +469,7 @@ mcl_mobs.register_arrow("mobs_mc:wither_skull", {
 	-- direct hit
 	hit_player = function(self, player)
 		local pos = vector.new(self.object:get_pos())
-		mcl_mobs.effect_functions["withering"](player, 0.5, 10)
+		mcl_potions.give_effect("withering", player, 2, 10)
 		player:punch(self.object, 1.0, {
 			full_punch_interval = 0.5,
 			damage_groups = {fleshy = 8},
@@ -484,7 +484,7 @@ mcl_mobs.register_arrow("mobs_mc:wither_skull", {
 
 	hit_mob = function(self, mob)
 		local pos = vector.new(self.object:get_pos())
-		mcl_mobs.effect_functions["withering"](mob, 0.5, 10)
+		mcl_potions.give_effect("withering", mob, 2, 10)
 		mob:punch(self.object, 1.0, {
 			full_punch_interval = 0.5,
 			damage_groups = {fleshy = 8},
@@ -522,7 +522,7 @@ mcl_mobs.register_arrow("mobs_mc:wither_skull_strong", {
 	-- direct hit
 	hit_player = function(self, player)
 		local pos = vector.new(self.object:get_pos())
-		mcl_mobs.effect_functions["withering"](player, 0.5, 10)
+		mcl_potions.give_effect("withering", player, 2, 10)
 		player:punch(self.object, 1.0, {
 			full_punch_interval = 0.5,
 			damage_groups = {fleshy = 12},
@@ -541,7 +541,7 @@ mcl_mobs.register_arrow("mobs_mc:wither_skull_strong", {
 
 	hit_mob = function(self, mob)
 		local pos = vector.new(self.object:get_pos())
-		mcl_mobs.effect_functions["withering"](mob, 0.5, 10)
+		mcl_potions.give_effect("withering", mob, 2, 10)
 		mob:punch(self.object, 1.0, {
 			full_punch_interval = 0.5,
 			damage_groups = {fleshy = 12},
diff --git a/mods/ITEMS/mcl_potions/init.lua b/mods/ITEMS/mcl_potions/init.lua
index d70e14f36..cdc095203 100644
--- a/mods/ITEMS/mcl_potions/init.lua
+++ b/mods/ITEMS/mcl_potions/init.lua
@@ -633,19 +633,6 @@ function mcl_potions.get_alchemy(ingr, pot)
 	return false
 end
 
--- TODO replace all calls to the old API with new API calls in other mods
--- mcl_mobs.effect_functions["poison"] = mcl_potions.poison_func
--- mcl_mobs.effect_functions["regeneration"] = mcl_potions.regeneration_func
--- mcl_mobs.effect_functions["invisibility"] = mcl_potions.invisiblility_func
--- mcl_mobs.effect_functions["fire_resistance"] = mcl_potions.fire_resistance_func
--- mcl_mobs.effect_functions["night_vision"] = mcl_potions.night_vision_func
--- mcl_mobs.effect_functions["water_breathing"] = mcl_potions.water_breathing_func
--- mcl_mobs.effect_functions["leaping"] = mcl_potions.leaping_func
--- mcl_mobs.effect_functions["swiftness"] = mcl_potions.swiftness_func
--- mcl_mobs.effect_functions["heal"] = mcl_potions.healing_func
--- mcl_mobs.effect_functions["bad_omen"] = mcl_potions.bad_omen_func
--- mcl_mobs.effect_functions["withering"] = mcl_potions.withering_func
-
 -- give withering to players in a wither rose
 local etime = 0
 minetest.register_globalstep(function(dtime)