diff --git a/apps/openmw/mwclass/potion.cpp b/apps/openmw/mwclass/potion.cpp
index 40b4d6234..c26b925f6 100644
--- a/apps/openmw/mwclass/potion.cpp
+++ b/apps/openmw/mwclass/potion.cpp
@@ -20,7 +20,7 @@
 #include "../mwrender/objects.hpp"
 #include "../mwrender/renderinginterface.hpp"
 
-#include "../mwmechanics/npcstats.hpp"
+#include "../mwmechanics/alchemy.hpp"
 
 namespace MWClass
 {
@@ -124,17 +124,8 @@ namespace MWClass
 
         // hide effects the player doesnt know about
         MWWorld::Ptr player = MWBase::Environment::get().getWorld ()->getPlayerPtr();
-        MWMechanics::NpcStats& npcStats = player.getClass().getNpcStats (player);
-        int alchemySkill = npcStats.getSkill (ESM::Skill::Alchemy).getBase();
-        int i=0;
-        static const float fWortChanceValue =
-                MWBase::Environment::get().getWorld()->getStore().get<ESM::GameSetting>().find("fWortChanceValue")->getFloat();
-        for (MWGui::Widgets::SpellEffectList::iterator it = info.effects.begin(); it != info.effects.end(); ++it)
-        {
-            it->mKnown = (i <= 1 && alchemySkill >= fWortChanceValue)
-                 || (i <= 3 && alchemySkill >= fWortChanceValue*2);
-            ++i;
-        }
+        for (unsigned int i=0; i<info.effects.size(); ++i)
+            info.effects[i].mKnown = MWMechanics::Alchemy::knownEffect(i, player);
 
         info.isPotion = true;
 
diff --git a/apps/openmw/mwgui/alchemywindow.cpp b/apps/openmw/mwgui/alchemywindow.cpp
index d12c22e06..3299846b7 100644
--- a/apps/openmw/mwgui/alchemywindow.cpp
+++ b/apps/openmw/mwgui/alchemywindow.cpp
@@ -216,6 +216,7 @@ namespace MWGui
 
         std::set<MWMechanics::EffectKey> effectIds = mAlchemy->listEffects();
         Widgets::SpellEffectList list;
+        unsigned int effectIndex=0;
         for (std::set<MWMechanics::EffectKey>::iterator it = effectIds.begin(); it != effectIds.end(); ++it)
         {
             Widgets::SpellEffectParams params;
@@ -228,7 +229,10 @@ namespace MWGui
             params.mIsConstant = true;
             params.mNoTarget = true;
 
+            params.mKnown = mAlchemy->knownEffect(effectIndex, MWBase::Environment::get().getWorld()->getPlayerPtr());
+
             list.push_back(params);
+            ++effectIndex;
         }
 
         while (mEffectsBox->getChildCount())
diff --git a/apps/openmw/mwmechanics/alchemy.cpp b/apps/openmw/mwmechanics/alchemy.cpp
index d39c88150..d02376d23 100644
--- a/apps/openmw/mwmechanics/alchemy.cpp
+++ b/apps/openmw/mwmechanics/alchemy.cpp
@@ -451,6 +451,16 @@ MWMechanics::Alchemy::TEffectsIterator MWMechanics::Alchemy::endEffects() const
     return mEffects.end();
 }
 
+bool MWMechanics::Alchemy::knownEffect(unsigned int potionEffectIndex, const MWWorld::Ptr &npc)
+{
+    MWMechanics::NpcStats& npcStats = npc.getClass().getNpcStats(npc);
+    int alchemySkill = npcStats.getSkill (ESM::Skill::Alchemy).getBase();
+    static const float fWortChanceValue =
+            MWBase::Environment::get().getWorld()->getStore().get<ESM::GameSetting>().find("fWortChanceValue")->getFloat();
+    return (potionEffectIndex <= 1 && alchemySkill >= fWortChanceValue)
+            || (potionEffectIndex <= 3 && alchemySkill >= fWortChanceValue*2);
+}
+
 MWMechanics::Alchemy::Result MWMechanics::Alchemy::create (const std::string& name)
 {
     if (mTools[ESM::Apparatus::MortarPestle].isEmpty())
diff --git a/apps/openmw/mwmechanics/alchemy.hpp b/apps/openmw/mwmechanics/alchemy.hpp
index caba26f14..f351881e0 100644
--- a/apps/openmw/mwmechanics/alchemy.hpp
+++ b/apps/openmw/mwmechanics/alchemy.hpp
@@ -80,6 +80,9 @@ namespace MWMechanics
 
         public:
 
+            static bool knownEffect (unsigned int potionEffectIndex, const MWWorld::Ptr& npc);
+            ///< Does npc have sufficient alchemy skill to know about this potion effect?
+
             void setAlchemist (const MWWorld::Ptr& npc);
             ///< Set alchemist and configure alchemy setup accordingly. \a npc may be empty to indicate that
             /// there is no alchemist (alchemy session has ended).