diff --git a/src/compiler.c b/src/compiler.c
index 270ab9d..8a9d093 100644
--- a/src/compiler.c
+++ b/src/compiler.c
@@ -850,6 +850,30 @@ normalDeclaration (Tac tc)
       levelDeclareConst (tc);
       if (level < 2 && tc->t3.tac == NULL)
 	knowledgeAddTermlist (sys->know, tacTermlist (tc->t1.tac));
+      if (level > 0)
+	{
+	  globalError++;
+	  warning_pre ();
+	  eprintf ("const ");
+	  termlistPrint (tacTermlist (tc->t1.tac));
+	  eprintf
+	    (" usage inside roles is deprecated. Please use 'fresh' instead on line %i.\n",
+	     tc->lineno);
+	  globalError--;
+	}
+      break;
+    case TAC_FRESH:
+      levelDeclareConst (tc);
+      if (level < 2)
+	{
+	  globalError++;
+	  error_pre ();
+	  eprintf ("fresh terms ");
+	  termlistPrint (tacTermlist (tc->t1.tac));
+	  eprintf (" should be declared inside roles,");
+	  errorTac (tc->lineno);	// exits Scyther here
+	  globalError--;
+	}
       break;
     case TAC_SECRET:
       levelDeclareConst (tc);
diff --git a/src/parser.y b/src/parser.y
index 4be7a29..c6469be 100644
--- a/src/parser.y
+++ b/src/parser.y
@@ -45,6 +45,7 @@ int yylex(void);
 %token 		CLAIMT
 %token 		VAR
 %token 		CONST
+%token 		FRESH
 %token 		RUN
 %token 		SECRET
 %token 		COMPROMISED
@@ -221,16 +222,22 @@ knowsdecl	: KNOWS termlist ';'
 
 declaration	: secretpref CONST basictermlist typeinfo1 ';'
 		  {	Tac t = tacCreate(TAC_CONST);
-		  	t->t1.tac = $3;
-			t->t2.tac = $4;
-			t->t3.tac = $1;
+		  	t->t1.tac = $3; // names
+			t->t2.tac = $4; // type
+			t->t3.tac = $1; // secret?
+			$$ = t;
+		  }
+		| FRESH basictermlist typeinfo1 ';'
+		  {	Tac t = tacCreate(TAC_FRESH);
+		  	t->t1.tac = $2;	// names
+			t->t2.tac = $3; // type
 			$$ = t;
 		  }
 		| secretpref VAR basictermlist typeinfoN ';'
 		  {	Tac t = tacCreate(TAC_VAR);
 		  	t->t1.tac = $3;
 			t->t2.tac = $4;
-			t->t3.tac = $1;
+			t->t3.tac = $1; // obsolete: should not even occur at the global level
 			$$ = t;
 		  }
 		| SECRET basictermlist typeinfo1 ';'
diff --git a/src/scanner.l b/src/scanner.l
index 77b6c2c..1690a98 100644
--- a/src/scanner.l
+++ b/src/scanner.l
@@ -162,6 +162,7 @@ recv		{ return RECVT; }
 send		{ return SENDT; }
 var		{ return VAR; }
 const		{ return CONST; }
+fresh		{ return FRESH; }
 claim		{ return CLAIMT; }
 run		{ return RUN; }
 secret		{ return SECRET; }
diff --git a/src/tac.h b/src/tac.h
index c6b6a16..6183d16 100644
--- a/src/tac.h
+++ b/src/tac.h
@@ -34,6 +34,7 @@ enum tactypes
   TAC_ENCRYPT,
   TAC_VAR,
   TAC_CONST,
+  TAC_FRESH,
   TAC_READ,
   TAC_SEND,
   TAC_CLAIM,