diff --git a/lib/inline-css.js b/lib/inline-css.js
index 43780d0..68dfe43 100644
--- a/lib/inline-css.js
+++ b/lib/inline-css.js
@@ -2,7 +2,7 @@ const parseCSS = require('css-rules');
 const cheerio = require('cheerio');
 const pseudoCheck = require('./pseudoCheck');
 const handleRule = require('./handleRule');
-const flatten = require('lodash.flatten');
+const flatten = require('flat-util');
 const setStyleAttrs = require('./setStyleAttrs');
 const setWidthAttrs = require('./setWidthAttrs');
 const removeClassId = require('./removeClassId');
diff --git a/package-lock.json b/package-lock.json
index a6d130b..f40e8e6 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -2468,6 +2468,11 @@
         }
       }
     },
+    "flat-util": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/flat-util/-/flat-util-1.0.0.tgz",
+      "integrity": "sha512-QWmuZqTxySvT2Z0YX6zuclkgWw3RwbVu4YcKEygPmcoopb3U93AoGSXJ8MHQQvejoz+2lJOe2S6fF3+icxyFBg=="
+    },
     "flatted": {
       "version": "2.0.1",
       "resolved": "https://registry.npmjs.org/flatted/-/flatted-2.0.1.tgz",
diff --git a/package.json b/package.json
index c594def..45d9b29 100644
--- a/package.json
+++ b/package.json
@@ -11,7 +11,7 @@
     "css-rules": "^1.0.6",
     "extend": "^3.0.2",
     "extract-css": "^1.5.0",
-    "lodash.flatten": "^4.4.0",
+    "flat-util": "^1.0.0",
     "object.pick": "^1.3.0",
     "slick": "^1.12.2",
     "specificity": "^0.4.1"