diff --git a/core/rawdb/chain_iterator.go b/core/rawdb/chain_iterator.go
index afa1aa7a4c..b8b8a4af0e 100644
--- a/core/rawdb/chain_iterator.go
+++ b/core/rawdb/chain_iterator.go
@@ -17,7 +17,6 @@
 package rawdb
 
 import (
-	"encoding/binary"
 	"runtime"
 	"sync/atomic"
 	"time"
@@ -380,34 +379,8 @@ func unindexTransactionsForTesting(db ethdb.Database, from uint64, to uint64, in
 // PruneTransactionIndex removes all tx index entries below a certain block number.
 func PruneTransactionIndex(db ethdb.Database, pruneBlock uint64) {
 	tail := ReadTxIndexTail(db)
-	if tail == nil || *tail > pruneBlock {
-		return // no index, or index ends above pruneBlock
+	if tail == nil || *tail >= pruneBlock {
+		return
 	}
-	// There are blocks below pruneBlock in the index. Iterate the entire index to remove
-	// their entries. Note if this fails, the index is messed up, but tail still points to
-	// the old tail.
-	var count, removed int
-	DeleteAllTxLookupEntries(db, func(txhash common.Hash, v []byte) bool {
-		count++
-		if count%10000000 == 0 {
-			log.Info("Pruning tx index", "count", count, "removed", removed)
-		}
-		if len(v) > 8 {
-			log.Error("Skipping legacy tx index entry", "hash", txhash)
-			return false
-		}
-		bn := decodeNumber(v)
-		if bn < pruneBlock {
-			removed++
-			return true
-		}
-		return false
-	})
-	WriteTxIndexTail(db, pruneBlock)
-}
-
-func decodeNumber(b []byte) uint64 {
-	var numBuffer [8]byte
-	copy(numBuffer[8-len(b):], b)
-	return binary.BigEndian.Uint64(numBuffer[:])
+	UnindexTransactions(db, *tail, pruneBlock, nil, true)
 }