diff --git a/x-pack/legacy/plugins/canvas/canvas_plugin_src/functions/server/esdocs.ts b/x-pack/legacy/plugins/canvas/canvas_plugin_src/functions/server/esdocs.ts
index fb118c841fffa..3dcc6807724b4 100644
--- a/x-pack/legacy/plugins/canvas/canvas_plugin_src/functions/server/esdocs.ts
+++ b/x-pack/legacy/plugins/canvas/canvas_plugin_src/functions/server/esdocs.ts
@@ -81,7 +81,7 @@ export function esdocs(): ExpressionFunction<'esdocs', Filter, Arguments, any> {
       });
 
       if (index) {
-        query.from(index.toLowerCase());
+        query.from(index);
       }
 
       if (fields) {
@@ -92,7 +92,7 @@ export function esdocs(): ExpressionFunction<'esdocs', Filter, Arguments, any> {
       if (sort) {
         const [sortField, sortOrder] = sort.split(',').map(str => str.trim());
         if (sortField) {
-          query.order(`"${sortField}"`, sortOrder.toLowerCase() === 'asc');
+          query.order(`"${sortField}"`, sortOrder === 'asc');
         }
       }
 
diff --git a/x-pack/legacy/plugins/canvas/public/components/es_index_select/es_index_select.js b/x-pack/legacy/plugins/canvas/public/components/es_index_select/es_index_select.js
index eff835e84e411..edc4506f20bda 100644
--- a/x-pack/legacy/plugins/canvas/public/components/es_index_select/es_index_select.js
+++ b/x-pack/legacy/plugins/canvas/public/components/es_index_select/es_index_select.js
@@ -18,7 +18,7 @@ export const ESIndexSelect = ({ value, loading, indices, onChange, onFocus, onBl
   return (
     <EuiComboBox
       selectedOptions={selectedOption}
-      onChange={([index]) => onChange(get(index, 'label', defaultIndex).toLowerCase())}
+      onChange={([index]) => onChange(get(index, 'label', defaultIndex))}
       onSearchChange={searchValue => {
         // resets input when user starts typing
         if (searchValue) {
diff --git a/x-pack/legacy/plugins/canvas/public/expression_types/datasources/esdocs.js b/x-pack/legacy/plugins/canvas/public/expression_types/datasources/esdocs.js
index ead7f58a851ba..ced1c51496d46 100644
--- a/x-pack/legacy/plugins/canvas/public/expression_types/datasources/esdocs.js
+++ b/x-pack/legacy/plugins/canvas/public/expression_types/datasources/esdocs.js
@@ -35,7 +35,7 @@ const EsdocsDatasource = ({ args, updateArgs, defaultIndex }) => {
   };
 
   const getIndex = () => {
-    return getSimpleArg('index', args)[0] || defaultIndex;
+    return getSimpleArg('index', args)[0] || '';
   };
 
   const getQuery = () => {
@@ -58,7 +58,11 @@ const EsdocsDatasource = ({ args, updateArgs, defaultIndex }) => {
   const fields = getFields();
   const [sortField, sortOrder] = getSortBy();
 
-  const index = getIndex().toLowerCase();
+  const index = getIndex();
+
+  if (!index && defaultIndex) {
+    setArg('index', defaultIndex);
+  }
 
   const sortOptions = [{ value: 'asc', text: 'Ascending' }, { value: 'desc', text: 'Descending' }];
 
diff --git a/x-pack/legacy/plugins/canvas/public/lib/es_service.js b/x-pack/legacy/plugins/canvas/public/lib/es_service.js
index d94ef0d518a06..6a6f4073b065a 100644
--- a/x-pack/legacy/plugins/canvas/public/lib/es_service.js
+++ b/x-pack/legacy/plugins/canvas/public/lib/es_service.js
@@ -42,8 +42,13 @@ export const getIndices = () =>
     })
     .catch(err => notify.error(err, { title: `Couldn't fetch Elasticsearch indices` }));
 
-export const getDefaultIndex = () =>
-  savedObjectsClient
-    .get('index-pattern', AdvancedSettings.get('defaultIndex'))
-    .then(defaultIndex => defaultIndex.attributes.title)
-    .catch(err => notify.error(err, { title: `Couldn't fetch default index` }));
+export const getDefaultIndex = () => {
+  const defaultIndexId = AdvancedSettings.get('defaultIndex');
+
+  return defaultIndexId
+    ? savedObjectsClient
+        .get('index-pattern', defaultIndexId)
+        .then(defaultIndex => defaultIndex.attributes.title)
+        .catch(err => notify.error(err, { title: `Couldn't fetch default index` }))
+    : Promise.resolve('');
+};