diff --git a/Marlin/Marlin.pde b/Marlin/Marlin.pde
index 49753fb45d..51829a4965 100644
--- a/Marlin/Marlin.pde
+++ b/Marlin/Marlin.pde
@@ -98,7 +98,8 @@
 // M204 - Set default acceleration: S normal moves T filament only moves (M204 S3000 T7000) im mm/sec^2  also sets minimum segment time in ms (B20000) to prevent buffer underruns and M20 minimum feedrate
 // M205 -  advanced settings:  minimum travel speed S=while printing T=travel only,  B=minimum segment time X= maximum xy jerk, Z=maximum Z jerk
 // M206 - set additional homeing offset
-// M220 - set speed factor override percentage S:factor in percent
+// M220 S<factor in percent>- set speed factor override percentage
+// M221 S<factor in percent>- set extrude factor override percentage
 // M240 - Trigger a camera to take a photograph
 // M301 - Set PID parameters P I and D
 // M302 - Allow cold extrudes
@@ -126,6 +127,8 @@ bool axis_relative_modes[] = AXIS_RELATIVE_MODES;
 volatile int feedmultiply=100; //100->1 200->2
 int saved_feedmultiply;
 volatile bool feedmultiplychanged=false;
+volatile int extrudemultiply=100; //100->1 200->2
+volatile bool extrudemultiplychanged=false;
 float current_position[NUM_AXIS] = { 0.0, 0.0, 0.0, 0.0 };
 float add_homeing[3]={0,0,0};
 uint8_t active_extruder = 0;
@@ -332,9 +335,13 @@ void get_command()
     serial_char = MYSERIAL.read();
     if(serial_char == '\n' || serial_char == '\r' || serial_char == ':' || serial_count >= (MAX_CMD_SIZE - 1) ) 
     {
-      if(!serial_count) return; //if empty line
+      if(!serial_count) { //if empty line
+        comment_mode = false; //for new command
+        return;
+      }
       cmdbuffer[bufindw][serial_count] = 0; //terminate string
       if(!comment_mode){
+        comment_mode = false; //for new command
         fromsd[bufindw] = false;
         if(strstr(cmdbuffer[bufindw], "N") != NULL)
         {
@@ -411,9 +418,7 @@ void get_command()
         }
         bufindw = (bufindw + 1)%BUFSIZE;
         buflen += 1;
-
       }
-      comment_mode = false; //for new command
       serial_count = 0; //clear buffer
     }
     else
@@ -447,10 +452,9 @@ void get_command()
         card.checkautostart(true);
         
       }
-      if(serial_char=='\n')
-         comment_mode = false; //for new command
       if(!serial_count)
       {
+        comment_mode = false; //for new command
         return; //if empty line
       }
       cmdbuffer[bufindw][serial_count] = 0; //terminate string
@@ -459,6 +463,7 @@ void get_command()
         buflen += 1;
         bufindw = (bufindw + 1)%BUFSIZE;
       }     
+      comment_mode = false; //for new command
       serial_count = 0; //clear buffer
     }
     else
@@ -1100,8 +1105,14 @@ void process_commands()
       }
     }
     break;
-    
-    
+    case 221: // M221 S<factor in percent>- set extrude factor override percentage
+    {
+      if(code_seen('S')) 
+      {
+        extrudemultiply = code_value() ;
+        extrudemultiplychanged=true;
+    }
+    break;
 
     #ifdef PIDTEMP
     case 301: // M301
diff --git a/Marlin/planner.cpp b/Marlin/planner.cpp
index 468d9fcac2..c4b998322a 100644
--- a/Marlin/planner.cpp
+++ b/Marlin/planner.cpp
@@ -81,6 +81,8 @@ long position[4];   //rescaled from extern when axis_steps_per_unit are changed
 static float previous_speed[4]; // Speed of previous path line segment
 static float previous_nominal_speed; // Nominal speed of previous path line segment
 
+extern volatile int extrudemultiply; // Sets extrude multiply factor (in percent)
+
 #ifdef AUTOTEMP
     float autotemp_max=250;
     float autotemp_min=210;
@@ -474,8 +476,6 @@ void plan_buffer_line(float &x, float &y, float &z, float &e, float feed_rate, u
   target[Z_AXIS] = lround(z*axis_steps_per_unit[Z_AXIS]);     
   target[E_AXIS] = lround(e*axis_steps_per_unit[E_AXIS]);
   
-
-  
   #ifdef PREVENT_DANGEROUS_EXTRUDE
     if(target[E_AXIS]!=position[E_AXIS])
     if(degHotend(active_extruder)<EXTRUDE_MINTEMP && !allow_cold_extrude)
@@ -503,6 +503,8 @@ void plan_buffer_line(float &x, float &y, float &z, float &e, float feed_rate, u
   block->steps_y = labs(target[Y_AXIS]-position[Y_AXIS]);
   block->steps_z = labs(target[Z_AXIS]-position[Z_AXIS]);
   block->steps_e = labs(target[E_AXIS]-position[E_AXIS]);
+  block->steps_e *= extrudemultiply;
+  block-?steps_e /= 100;
   block->step_event_count = max(block->steps_x, max(block->steps_y, max(block->steps_z, block->steps_e)));
 
   // Bail if this is a zero-length block
@@ -531,7 +533,7 @@ void plan_buffer_line(float &x, float &y, float &z, float &e, float feed_rate, u
   delta_mm[X_AXIS] = (target[X_AXIS]-position[X_AXIS])/axis_steps_per_unit[X_AXIS];
   delta_mm[Y_AXIS] = (target[Y_AXIS]-position[Y_AXIS])/axis_steps_per_unit[Y_AXIS];
   delta_mm[Z_AXIS] = (target[Z_AXIS]-position[Z_AXIS])/axis_steps_per_unit[Z_AXIS];
-  delta_mm[E_AXIS] = (target[E_AXIS]-position[E_AXIS])/axis_steps_per_unit[E_AXIS];
+  delta_mm[E_AXIS] = ((target[E_AXIS]-position[E_AXIS])/axis_steps_per_unit[E_AXIS])*extrudemultiply/100.0;
   if ( block->steps_x == 0 && block->steps_y == 0 && block->steps_z == 0 ) {
     block->millimeters = abs(delta_mm[E_AXIS]);
   } else {