diff --git a/core/vm/opcodes.go b/core/vm/opcodes.go
index cf9a26231b03..d61508cf9d47 100644
--- a/core/vm/opcodes.go
+++ b/core/vm/opcodes.go
@@ -208,13 +208,6 @@ const (
 	LOG4
 )
 
-// unofficial opcodes used for parsing.
-const (
-	PUSH OpCode = 0xb0 + iota
-	DUP
-	SWAP
-)
-
 // 0xf0 range - closures.
 const (
 	CREATE       OpCode = 0xf0
@@ -395,10 +388,6 @@ var opCodeToString = map[OpCode]string{
 	REVERT:       "REVERT",
 	INVALID:      "INVALID",
 	SELFDESTRUCT: "SELFDESTRUCT",
-
-	PUSH: "PUSH",
-	DUP:  "DUP",
-	SWAP: "SWAP",
 }
 
 func (op OpCode) String() string {