diff --git a/eth/trie/db.nim b/eth/trie/db.nim
index 050bd30..7e380b5 100644
--- a/eth/trie/db.nim
+++ b/eth/trie/db.nim
@@ -34,11 +34,15 @@ type
     containsProc: ContainsProc
     mostInnerTransaction: DbTransaction
 
+  TransactionFlags = enum
+    Committed
+    RolledBack
+
   DbTransaction* = ref object
     db: TrieDatabaseRef
     parentTransaction: DbTransaction
     modifications: MemoryLayer
-    committed: bool
+    flags: set[TransactionFlags]
 
 proc put*(db: TrieDatabaseRef, key, val: openarray[byte]) {.gcsafe.}
 proc get*(db: TrieDatabaseRef, key: openarray[byte]): Bytes {.gcsafe.}
@@ -137,24 +141,32 @@ proc rollback*(t: DbTransaction) =
   # Transactions should be handled in a strictly nested fashion.
   # Any child transaction must be committed or rolled-back before
   # its parent transactions:
-  doAssert t.db.mostInnerTransaction == t and not t.committed
+  doAssert t.db.mostInnerTransaction == t and
+    Committed notin t.flags and
+    RolledBack notin t.flags
   t.db.mostInnerTransaction = t.parentTransaction
+  t.flags.incl RolledBack
 
 proc commit*(t: DbTransaction) =
   # Transactions should be handled in a strictly nested fashion.
   # Any child transaction must be committed or rolled-back before
   # its parent transactions:
-  doAssert t.db.mostInnerTransaction == t and not t.committed
+  doAssert t.db.mostInnerTransaction == t and
+    Committed notin t.flags and
+    RolledBack notin t.flags
   t.db.mostInnerTransaction = t.parentTransaction
   t.modifications.commit(t.db)
-  t.committed = true
+  t.flags.incl Committed
 
 proc dispose*(t: DbTransaction) {.inline.} =
-  if not t.committed:
+  if Committed notin t.flags and
+     RolledBack notin t.flags:
     t.rollback()
 
 proc safeDispose*(t: DbTransaction) {.inline.} =
-  if t != nil and not t.committed:
+  if t != nil and
+     Committed notin t.flags and
+     RolledBack notin t.flags:
     t.rollback()
 
 proc putImpl[T](db: RootRef, key, val: openarray[byte]) =
diff --git a/tests/trie/test_transaction_db.nim b/tests/trie/test_transaction_db.nim
new file mode 100644
index 0000000..f55926f
--- /dev/null
+++ b/tests/trie/test_transaction_db.nim
@@ -0,0 +1,179 @@
+import
+  unittest, strutils, sequtils, os,
+  eth/trie/[db, trie_defs], ./testutils,
+  eth/rlp/types as rlpTypes
+
+suite "transaction db":
+  setup:
+    const
+      listLength = 30
+
+    var
+      keysA = randList(Bytes, randGen(3, 33), randGen(listLength))
+      valuesA = randList(Bytes, randGen(5, 77), randGen(listLength))
+      keysB = randList(Bytes, randGen(3, 33), randGen(listLength))
+      valuesB = randList(Bytes, randGen(5, 77), randGen(listLength))
+
+    proc populateA(db: TrieDatabaseRef) =
+      for i in 0 ..< listLength:
+        db.put(keysA[i], valuesA[i])
+
+    proc checkContentsA(db: TrieDatabaseRef): bool =
+      for i in 0 ..< listLength:
+        let v = db.get(keysA[i])
+        if v != valuesA[i]: return false
+      result = true
+
+    proc checkEmptyContentsA(db: TrieDatabaseRef): bool {.used.} =
+      for i in 0 ..< listLength:
+        let v = db.get(keysA[i])
+        if v.len != 0: return false
+      result = true
+
+    proc populateB(db: TrieDatabaseRef) {.used.} =
+      for i in 0 ..< listLength:
+        db.put(keysB[i], valuesB[i])
+
+    proc checkContentsB(db: TrieDatabaseRef): bool {.used.} =
+      for i in 0 ..< listLength:
+        let v = db.get(keysB[i])
+        if v != valuesB[i]: return false
+      result = true
+
+    proc checkEmptyContentsB(db: TrieDatabaseRef): bool {.used.} =
+      for i in 0 ..< listLength:
+        let v = db.get(keysB[i])
+        if v.len != 0: return false
+      result = true
+
+  test "commit":
+    var db = newMemoryDB()
+    var tx = db.beginTransaction()
+    db.populateA()
+    check checkContentsA(db)
+    tx.commit()
+    check checkContentsA(db)
+
+  test "rollback":
+    var db = newMemoryDB()
+    var tx = db.beginTransaction()
+    db.populateA()
+    check checkContentsA(db)
+    tx.rollback()
+    check checkEmptyContentsA(db)
+
+  test "dispose":
+    var db = newMemoryDB()
+    var tx = db.beginTransaction()
+    db.populateA()
+    check checkContentsA(db)
+    tx.dispose()
+    check checkEmptyContentsA(db)
+
+  test "commit dispose":
+    var db = newMemoryDB()
+    var tx = db.beginTransaction()
+    db.populateA()
+    check checkContentsA(db)
+    tx.commit()
+    tx.dispose()
+    check checkContentsA(db)
+
+  test "rollback dispose":
+    var db = newMemoryDB()
+    var tx = db.beginTransaction()
+    db.populateA()
+    check checkContentsA(db)
+    tx.rollback()
+    tx.dispose()
+    check checkEmptyContentsA(db)
+
+  test "dispose dispose":
+    var db = newMemoryDB()
+    var tx = db.beginTransaction()
+    db.populateA()
+    check checkContentsA(db)
+    tx.dispose()
+    tx.dispose()
+    check checkEmptyContentsA(db)
+
+  test "commit commit":
+    var db = newMemoryDB()
+    var txA = db.beginTransaction()
+    db.populateA()
+    var txB = db.beginTransaction()
+    db.populateB()
+
+    check checkContentsA(db)
+    check checkContentsB(db)
+
+    txB.commit()
+    txA.commit()
+
+    check checkContentsA(db)
+    check checkContentsB(db)
+
+  test "commit rollback":
+    var db = newMemoryDB()
+    var txA = db.beginTransaction()
+    db.populateA()
+    var txB = db.beginTransaction()
+    db.populateB()
+
+    check checkContentsA(db)
+    check checkContentsB(db)
+
+    txB.rollback()
+    txA.commit()
+
+    check checkContentsA(db)
+    check checkEmptyContentsB(db)
+
+  test "rollback commit":
+    var db = newMemoryDB()
+    var txA = db.beginTransaction()
+    db.populateA()
+    var txB = db.beginTransaction()
+    db.populateB()
+
+    check checkContentsA(db)
+    check checkContentsB(db)
+
+    txB.commit()
+    txA.rollback()
+
+    check checkEmptyContentsB(db)
+    check checkEmptyContentsA(db)
+
+  test "rollback rollback":
+    var db = newMemoryDB()
+    var txA = db.beginTransaction()
+    db.populateA()
+    var txB = db.beginTransaction()
+    db.populateB()
+
+    check checkContentsA(db)
+    check checkContentsB(db)
+
+    txB.rollback()
+    txA.rollback()
+
+    check checkEmptyContentsB(db)
+    check checkEmptyContentsA(db)
+
+  test "commit rollback dispose":
+    var db = newMemoryDB()
+    var txA = db.beginTransaction()
+    db.populateA()
+    var txB = db.beginTransaction()
+    db.populateB()
+
+    check checkContentsA(db)
+    check checkContentsB(db)
+
+    txB.rollback()
+    txA.commit()
+    txA.dispose()
+
+    check checkContentsA(db)
+    check checkEmptyContentsB(db)
diff --git a/tests/trie/testutils.nim b/tests/trie/testutils.nim
index b6f7075..51c8ebe 100644
--- a/tests/trie/testutils.nim
+++ b/tests/trie/testutils.nim
@@ -27,6 +27,11 @@ proc randString*(len: int): string =
   for i in 0..<len:
     result[i] = rand(255).char
 
+proc randBytes*(len: int): Bytes =
+  result = newSeq[byte](len)
+  for i in 0..<len:
+    result[i] = rand(255).byte
+
 proc toBytesRange*(str: string): BytesRange =
   var s: seq[byte]
   if str[0] == '0' and str[1] == 'x':
@@ -44,6 +49,8 @@ proc randPrimitives*[T](val: int): T =
     result = val
   elif T is BytesRange:
     result = randString(val).toRange
+  elif T is Bytes:
+    result = randBytes(val)
 
 proc randList*(T: typedesc, strGen, listGen: RandGen, unique: bool = true): seq[T] =
   let listLen = listGen.getVal()
@@ -82,4 +89,3 @@ proc genBitVec*(len: int): BitRange =
   result = bits(s, len)
   for i in 0..<len:
     result[i] = rand(2) == 1
-