diff --git a/api/database.php b/api/database.php
index 9bb0819..662d136 100644
--- a/api/database.php
+++ b/api/database.php
@@ -53,7 +53,7 @@ function initializeDB(PDO $db): void {
         CREATE TABLE IF NOT EXISTS transactions (
             id INTEGER PRIMARY KEY AUTOINCREMENT,
             product_id INTEGER NOT NULL,
-            type TEXT NOT NULL CHECK(type IN ('in', 'out')),
+            type TEXT NOT NULL CHECK(type IN ('in', 'out', 'waste')),
             quantity REAL NOT NULL,
             location TEXT NOT NULL DEFAULT 'dispensa',
             notes TEXT DEFAULT '',
@@ -77,6 +77,28 @@ function migrateDB(PDO $db): void {
         $db->exec("ALTER TABLE products ADD COLUMN package_unit TEXT DEFAULT ''");
     }
 
+    // Migrate transactions CHECK constraint to allow 'waste' type
+    $sql = $db->query("SELECT sql FROM sqlite_master WHERE type='table' AND name='transactions'")->fetchColumn();
+    if ($sql && strpos($sql, "'waste'") === false) {
+        $db->exec("ALTER TABLE transactions RENAME TO transactions_old");
+        $db->exec("
+            CREATE TABLE transactions (
+                id INTEGER PRIMARY KEY AUTOINCREMENT,
+                product_id INTEGER NOT NULL,
+                type TEXT NOT NULL CHECK(type IN ('in', 'out', 'waste')),
+                quantity REAL NOT NULL,
+                location TEXT NOT NULL DEFAULT 'dispensa',
+                notes TEXT DEFAULT '',
+                created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+                FOREIGN KEY (product_id) REFERENCES products(id) ON DELETE CASCADE
+            )
+        ");
+        $db->exec("INSERT INTO transactions SELECT * FROM transactions_old");
+        $db->exec("DROP TABLE transactions_old");
+        $db->exec("CREATE INDEX IF NOT EXISTS idx_transactions_product ON transactions(product_id)");
+        $db->exec("CREATE INDEX IF NOT EXISTS idx_transactions_date ON transactions(created_at)");
+    }
+
     // --- New shared tables ---
     // app_settings: key-value store shared across all devices
     $tables = $db->query("SELECT name FROM sqlite_master WHERE type='table' AND name='app_settings'")->fetchAll();
diff --git a/data/dispensa.db b/data/dispensa.db
index c21fdc0..e5d06e0 100644
Binary files a/data/dispensa.db and b/data/dispensa.db differ