diff --git a/src/main/java/cn/nukkit/entity/Effect.java b/src/main/java/cn/nukkit/entity/Effect.java
index e7a1b4d8b6..d04242e044 100644
--- a/src/main/java/cn/nukkit/entity/Effect.java
+++ b/src/main/java/cn/nukkit/entity/Effect.java
@@ -187,7 +187,7 @@ public boolean canTick() {
                 return true;
             case Effect.SPEED:
             case Effect.SLOWNESS:
-                return true;
+                return (this.duration % 20) == 0;
         }
         return false;
     }
@@ -247,6 +247,14 @@ public void add(Entity entity, boolean modify) {
             }
 
             ((Player) entity).dataPacket(pk);
+            
+            if (this.id == Effect.SPEED) {
+                ((Player) entity).setMovementSpeed(0.1f + (this.amplifier + 1) * 0.01f);
+            }
+
+            if (this.id == Effect.SLOWNESS) {
+                ((Player) entity).setMovementSpeed(0.1f - (this.amplifier + 1) * 0.01f);
+            }
         }
 
         if (this.id == Effect.INVISIBILITY) {
@@ -263,6 +271,10 @@ public void remove(Entity entity) {
             pk.eventId = MobEffectPacket.EVENT_REMOVE;
 
             ((Player) entity).dataPacket(pk);
+            
+            if (this.id == Effect.SPEED || this.id == Effect.SLOWNESS) {
+                ((Player) entity).setMovementSpeed(0.1f);
+            }
         }
 
         if (this.id == Effect.INVISIBILITY) {