diff --git a/include/catch_runner.hpp b/include/catch_runner.hpp
index 97bddba3..57e5aa99 100644
--- a/include/catch_runner.hpp
+++ b/include/catch_runner.hpp
@@ -142,9 +142,8 @@ namespace Catch {
 
         int applyCommandLine( int argc, char* const argv[], OnUnusedOptions::DoWhat unusedOptionBehaviour = OnUnusedOptions::Fail ) {
             try {
+                m_cli.setThrowOnUnrecognisedTokens( unusedOptionBehaviour == OnUnusedOptions::Fail );
                 m_unusedTokens = m_cli.parseInto( argc, argv, m_configData );
-                if( unusedOptionBehaviour == OnUnusedOptions::Fail )
-                    enforceNoUsedTokens();
                 if( m_configData.showHelp )
                     showHelp( m_configData.processName );
                 m_config.reset();
@@ -152,7 +151,7 @@ namespace Catch {
             catch( std::exception& ex ) {
                 {
                     Colour colourGuard( Colour::Red );
-                    std::cerr   << "\nError in input:\n"
+                    std::cerr   << "\nError(s) in input:\n"
                                 << Text( ex.what(), TextAttributes().setIndent(2) )
                                 << "\n\n";
                 }
@@ -167,18 +166,6 @@ namespace Catch {
             m_config.reset();
         }
 
-        void enforceNoUsedTokens() const {
-            if( !m_unusedTokens.empty() ) {
-                std::vector<Clara::Parser::Token>::const_iterator
-                    it = m_unusedTokens.begin(),
-                    itEnd = m_unusedTokens.end();
-                std::string msg;
-                for(; it != itEnd; ++it )
-                    msg += "  unrecognised option: " + it->data + "\n";
-                throw std::runtime_error( msg.substr( 0, msg.size()-1 ) );
-            }
-        }
-
         int run( int argc, char* const argv[] ) {
 
             int returnCode = applyCommandLine( argc, argv );
diff --git a/include/internal/clara.h b/include/internal/clara.h
index a401edd8..9f736e99 100644
--- a/include/internal/clara.h
+++ b/include/internal/clara.h
@@ -371,18 +371,25 @@ namespace Clara {
 
         CommandLine()
         :   m_boundProcessName( new Detail::NullBinder<ConfigT>() ),
-            m_highestSpecifiedArgPosition( 0 )
+            m_highestSpecifiedArgPosition( 0 ),
+            m_throwOnUnrecognisedTokens( false )
         {}
         CommandLine( CommandLine const& other )
         :   m_boundProcessName( other.m_boundProcessName ),
             m_options ( other.m_options ),
             m_positionalArgs( other.m_positionalArgs ),
-            m_highestSpecifiedArgPosition( other.m_highestSpecifiedArgPosition )
+            m_highestSpecifiedArgPosition( other.m_highestSpecifiedArgPosition ),
+            m_throwOnUnrecognisedTokens( other.m_throwOnUnrecognisedTokens )
         {
             if( other.m_arg.get() )
                 m_arg = ArgAutoPtr( new Arg( *other.m_arg ) );
         }
 
+        CommandLine& setThrowOnUnrecognisedTokens( bool shouldThrow = true ) {
+            m_throwOnUnrecognisedTokens = shouldThrow;
+            return *this;
+        }
+
         template<typename F>
         ArgBinder bind( F f ) {
             ArgBinder binder( this, f );
@@ -488,6 +495,7 @@ namespace Clara {
 
         std::vector<Parser::Token> populateOptions( std::vector<Parser::Token> const& tokens, ConfigT& config ) const {
             std::vector<Parser::Token> unusedTokens;
+            std::vector<std::string> errors;
             for( std::size_t i = 0; i < tokens.size(); ++i ) {
                 Parser::Token const& token = tokens[i];
                 typename std::vector<Arg>::const_iterator it = m_options.begin(), itEnd = m_options.end();
@@ -499,8 +507,9 @@ namespace Clara {
                             ( token.type == Parser::Token::LongOpt && arg.hasLongName( token.data ) ) ) {
                             if( arg.takesArg() ) {
                                 if( i == tokens.size()-1 || tokens[i+1].type != Parser::Token::Positional )
-                                    throw std::domain_error( "Expected argument to option " + token.data );
-                                arg.boundField.set( config, tokens[++i].data );
+                                    errors.push_back( "Expected argument to option: " + token.data );
+                                else
+                                    arg.boundField.set( config, tokens[++i].data );
                             }
                             else {
                                 arg.boundField.setFlag( config );
@@ -509,11 +518,26 @@ namespace Clara {
                         }
                     }
                     catch( std::exception& ex ) {
-                        throw std::runtime_error( std::string( ex.what() ) + "\n- while parsing: (" + arg.commands() + ")" );
+                        errors.push_back( std::string( ex.what() ) + "\n- while parsing: (" + arg.commands() + ")" );
                     }
                 }
-                if( it == itEnd )
-                    unusedTokens.push_back( token );
+                if( it == itEnd ) {
+                    if( token.type == Parser::Token::Positional || !m_throwOnUnrecognisedTokens )
+                        unusedTokens.push_back( token );
+                    else if( m_throwOnUnrecognisedTokens )
+                        errors.push_back( "unrecognised option: " + token.data );
+                }
+            }
+            if( !errors.empty() ) {
+                std::ostringstream oss;
+                for( std::vector<std::string>::const_iterator it = errors.begin(), itEnd = errors.end();
+                        it != itEnd;
+                        ++it ) {
+                    if( it != errors.begin() )
+                        oss << "\n";
+                    oss << *it;
+                }
+                throw std::runtime_error( oss.str() );
             }
             return unusedTokens;
         }
@@ -552,6 +576,7 @@ namespace Clara {
         std::map<int, Arg> m_positionalArgs;
         ArgAutoPtr m_arg;
         int m_highestSpecifiedArgPosition;
+        bool m_throwOnUnrecognisedTokens;
     };
 
 } // end namespace Clara
diff --git a/projects/SelfTest/CmdLineTests.cpp b/projects/SelfTest/CmdLineTests.cpp
index 968a1529..3eb54d2f 100644
--- a/projects/SelfTest/CmdLineTests.cpp
+++ b/projects/SelfTest/CmdLineTests.cpp
@@ -116,7 +116,7 @@ TEST_CASE( "cmdline" ) {
             .shortOpt( "d" )
             .longOpt( "description" )
             .hint( "some text" );
-        
+
         const char* argv[] = { "test", "-n 42", "-d some text" };
         std::vector<Clara::Parser::Token> unusedTokens = parseInto( cli, argv, config1 );