diff --git a/docs/reference/query-dsl/queries/mlt-query.asciidoc b/docs/reference/query-dsl/queries/mlt-query.asciidoc
index 3ebc7b24fcd16..bbd0ae16a086a 100644
--- a/docs/reference/query-dsl/queries/mlt-query.asciidoc
+++ b/docs/reference/query-dsl/queries/mlt-query.asciidoc
@@ -46,7 +46,6 @@ If only one document is specified, the query behaves the same as the
 }
 --------------------------------------------------
 
-
 `more_like_this` can be shortened to `mlt`.
 
 Under the hood, `more_like_this` simply creates multiple `should` clauses in a `bool` query of
@@ -61,26 +60,29 @@ such as `min_word_length`, `max_word_length` or `stop_words`, to control what
 terms should be considered as interesting. In order to give more weight to
 more interesting terms, each boolean clause associated with a term could be
 boosted by the term tf-idf score times some boosting factor `boost_terms`.
-
 When a search for multiple `docs` is issued, More Like This generates a
 `more_like_this` query per document field in `fields`. These `fields` are
 specified as a top level parameter or within each `doc`.
 
+IMPORTANT: The fields must be indexed and of type `string`. Additionally, when
+using `ids` or `docs`, the fields must be either `stored`, store `term_vector`
+or `_source` must be enabled.
+
 The `more_like_this` top level parameters include:
 
 [cols="<,<",options="header",]
 |=======================================================================
 |Parameter |Description
 |`fields` |A list of the fields to run the more like this query against.
-Defaults to the `_all` field.
+Defaults to the `_all` field for `like_text` and to all possible fields
+for `ids` or `docs`.
 
 |`like_text` |The text to find documents like it, *required* if `ids` or `docs` are
 not specified.
 
 |`ids` or `docs` |A list of documents following the same syntax as the 
-<<docs-multi-get,Multi GET API>>. This parameter is *required* if
-`like_text` is not specified. The texts are fetched from `fields` unless
-specified in each `doc`, and cannot be set to `_all`.
+<<docs-multi-get,Multi GET API>>. The text is fetched from `fields`
+unless specified otherwise in each `doc`.
 
 |`include` |When using `ids` or `docs`, specifies whether the documents should be
 included from the search. Defaults to `false`.
diff --git a/src/main/java/org/elasticsearch/index/query/MoreLikeThisQueryParser.java b/src/main/java/org/elasticsearch/index/query/MoreLikeThisQueryParser.java
index 0cc50a44bb189..f94dee7254fc9 100644
--- a/src/main/java/org/elasticsearch/index/query/MoreLikeThisQueryParser.java
+++ b/src/main/java/org/elasticsearch/index/query/MoreLikeThisQueryParser.java
@@ -164,28 +164,34 @@ public Query parse(QueryParseContext parseContext) throws IOException, QueryPars
         if (mltQuery.getLikeText() == null && items.isEmpty()) {
             throw new QueryParsingException(parseContext.index(), "more_like_this requires at least 'like_text' or 'ids/docs' to be specified");
         }
+        if (moreLikeFields != null && moreLikeFields.isEmpty()) {
+            throw new QueryParsingException(parseContext.index(), "more_like_this requires 'fields' to be non-empty");
+        }
 
+        // set analyzer
         if (analyzer == null) {
             analyzer = parseContext.mapperService().searchAnalyzer();
         }
         mltQuery.setAnalyzer(analyzer);
 
-        if (moreLikeFields == null) {
+        // set like text fields
+        boolean useDefaultField = (moreLikeFields == null);
+        if (useDefaultField) {
             moreLikeFields = Lists.newArrayList(parseContext.defaultField());
-        } else if (moreLikeFields.isEmpty()) {
-            throw new QueryParsingException(parseContext.index(), "more_like_this requires 'fields' to be non-empty");
         }
-
+        // possibly remove unsupported fields
         removeUnsupportedFields(moreLikeFields, analyzer, failOnUnsupportedField);
         if (moreLikeFields.isEmpty()) {
             return null;
         }
         mltQuery.setMoreLikeFields(moreLikeFields.toArray(Strings.EMPTY_ARRAY));
 
+        // support for named query
         if (queryName != null) {
             parseContext.addNamedQuery(queryName, mltQuery);
         }
 
+        // handle items
         if (!items.isEmpty()) {
             // set default index, type and fields if not specified
             for (MultiGetRequest.Item item : items) {
@@ -201,7 +207,11 @@ public Query parse(QueryParseContext parseContext) throws IOException, QueryPars
                     }
                 }
                 if (item.fields() == null && item.fetchSourceContext() == null) {
-                    item.fields(moreLikeFields.toArray(new String[moreLikeFields.size()]));
+                    if (useDefaultField) {
+                        item.fields("*");
+                    } else {
+                        item.fields(moreLikeFields.toArray(new String[moreLikeFields.size()]));
+                    }
                 }
             }
             // fetching the items with multi-termvectors API